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The keto flu, other keto side effects, and how to cure them

The keto flu

Symptoms of the keto flu:

  • Fatigue
  • Headache
  • Irritability
  • Difficulty focusing (“brain fog”)
  • Lack of motivation
  • Dizziness
  • Sugar cravings
  • Nausea
  • Muscle cramps

The cause

The keto flu is caused by your body’s transition from burning sugar to burning fat for most of its energy needs.

Switching from a high-carb diet to a very-low-carb diet lowers insulin levels in your body. This is not only healthy but also one of the primary goals of a ketogenic diet. When insulin levels are very low, your liver begins converting fat into ketones, which most of your cells can use in place of glucose. When your body is mainly using ketones and fat for energy, you’re in a state of ketosis.

However, it takes your brain and other organs some time to adapt to using this new fuel. When your insulin levels drop, your body responds by excreting more sodium in the urine, along with water. Because of this, you’ll probably find yourself urinating a lot more often in the first week or so of a keto diet.

This change is responsible for some of the rapid – and usually very welcome! – weight loss that happens in the early stages of a keto diet. However, losing a lot of water and sodium is responsible for many of the unpleasant symptoms of keto flu.

It’s well known that response to the keto transition is very individual. Some people may feel fine or slightly tired for a day or two after starting keto. At the other extreme, there are those who develop symptoms that strongly impact their ability to function for several days.

However, the keto flu doesn’t have to be unbearable for anyone if the proper steps are taken to remedy it.

The cure for the keto flu

Symptoms of the keto flu usually disappear by themselves within a few days, as the body adapts. But rather than suffering needlessly during this time, why not address the cause and start feeling better right now? The first step is by far the most important, and it’s often all that’s needed.

1. Top tip: increase your salt and water intake

Since loss of salt and water is responsible for most keto flu issues, increasing your intake of both can help reduce your symptoms significantly and often eliminate them altogether.12

During the first few weeks of your keto lifestyle, whenever you develop a headache, lethargy, nausea, dizziness or other symptoms, drink a glass of water with half a teaspoon of salt stirred into it. This simple action may alleviate your keto flu symptoms within 15 to 30 minutes. Feel free to do this twice a day or more, if needed.

Or for a tasty alternative, drink consommé, bouillon, bone broth, chicken stock or beef stock — and stir in a spoonful of salted butter, if you like. Or, if you’re using low-sodium bone broth or stock, add a pinch or two of salt.

In addition, make sure you’re drinking enough water. The larger you are, the more water you’ll probably lose in the early stages of keto, and the more you’ll need to replace. A good rule of thumb is to drink a minimum of 3 liters of fluid every day during the first week of your keto diet.

This doesn’t mean you must drink 3-plus liters of plain water in addition to your other beverages. Although drinking plenty of water is important, coffee and tea will contribute toward your fluid intake as well.

Getting enough water, sodium and other electrolytes can also help with another issue people often experience in the early stages of a keto diet: constipation.

Learn more about electrolyte supplementation on a keto diet

2. More fat = fewer symptoms

Increasing salt and fluid intake usually resolves most of the keto flu side effects. However, if you continue feeling poorly after following those recommendations, try eating more fat.

Due to decades of misinformation about fat being unhealthy, fat phobia is common among people who come to low-carb ketogenic eating. However, if you sharply lower your carb intake without upping your fat consumption, your body will think it is starving. You will feel tired, hungry and miserable.

A well-balanced keto diet includes enough fat so that you are not hungry after a meal, can go for several hours without eating, and have ample energy. Make sure to increase your intake of fat at the start of your keto journey until your body adapts to using fat and ketones for most of its energy needs. Once you’re fat adapted, let your appetite guide you in cutting back on fat a bit until you reach the point where you can easily maintain the balance between hunger and satiety.

In short: When in doubt, add fat (mmm, butter). Or follow our keto recipes, which have enough fat in relation to carbs and protein.

3. Slower transition

Has adding more water, salt and fat not helped very much? Are you still feeling achy, tired and off? We recommend you try to endure it for a few more days until the symptoms pass. Research has shown that a very-low-carb diet is best for weight loss and metabolic issues like type 2 diabetes.3Keto flu symptoms are only temporary – they’ll be long gone when you are a fat burner.

You can, however, slow down the transition to ketogenic eating by consuming a few more carbs, such as following a more moderate low-carb diet that provides 20 to 50 grams of carbs a day.

Eating slightly more carbs may potentially slow down weight loss and mute rapid, dramatic health improvements, but it can still lead to better health, especially if you are cutting out sugar and processed foods. And keto flu will no longer be an issue. Once you’ve adapted to low-carb eating, feel free to try eating less than 20 grams of carbs again to see whether your body prefers this or slightly higher carb intake.

4. Take it easy with physical activity

Although many people find that their energy and stamina improve on a keto lifestyle, trying to do too much in the early stages can worsen keto flu symptoms. Well-known ketogenic researcher Dr. Steve Phinney has conducted studies in endurance athletes4 as well as obese individuals5 demonstrating that physical performance decreases during the first week of very-low-carb eating. Fortunately, his research also shows that by week 4, people typically perform better than before they started keto.

Walking, stretching, or doing gentle yoga or other mind-body exercise should be fine and may even help you feel better. But when your body is already under stress from trying to adapt to a new fuel system, don’t place an additional burden on it by attempting any type of strenuous workout. Take it easy for the first few weeks and then slowly increase your exercise intensity.

5. Don’t consciously restrict food intake

Some people find that they aren’t very hungry the first week of keto because they are nauseated or have a headache that reduces their appetite.

However, others may get pretty hungry and worry that they’re eating too many calories or too much protein to achieve the kind of fast weight loss they’ve heard about.

The Atkins diet begins with induction, its strictest phase that allows for maximum fat burning and getting into ketosis quickly. On this diet, as long as carbs are restricted to 20 or fewer grams per day, you can eat as much of the allowed foods you need to feel full.

It’s not a good idea to focus on calories or macronutrients when you’re trying to become keto adapted. Letting yourself get hungry or stressing about the amount of food you’re eating may actually make keto flu symptoms worse. Once you’re steadily in ketosis, your appetite will likely go down, and you’ll naturally end up eating less.6

Eat as much of the allowed foods as needed until you are no longer hungry, and have carb-free snacks like hard-boiled eggs available in case hunger strikes between meals. On the other hand, make sure to avoid getting overly full by eating slowly and paying attention to hunger and fullness signals.

Dr. Eric Westman’s tips

Learn more about getting the best results and the least side effects on a ketogenic diet from world renowned keto expert Dr. Eric Westman. His five-part video course is on our membership site (one month free trial).

In video #3/5, he discusses how best to avoid transition problems like keto flu.

After my previous article explaining what is a keto diet, many have asked me to explain what is keto flu and how to avoid it!

In the original article above, I explain everything you need to know about starting a keto diet. What to enjoy. What to avoid. How to get started. There’s even a free FAQ and diet sheet too.

What is keto flu and how to avoid it?

So, you are interested in starting the keto diet, but you want to know everything about it first, and how to start it, the right way.

You have probably heard about the amazing benefits of the keto diet. It is incredible for fast and sustained weight loss, not to mention all the incredible health benefits that you can expect to experience.

Unfortunately, you may have also heard about the keto flu.

What is keto flu?

Keto flu is a real thing and it happens when you quickly jump into a keto diet. There are ways though, that you can avoid keto flu.

Keto flu is feeling the symptoms of “withdrawal” from carbs. Your body goes through changes when it switches from burning glucose to burning fat.

These withdrawal symptoms include dizziness, drowsiness, muscle aches, nausea, and irritability. All of these symptoms are a completely natural reaction to the changes your body is facing Do not despair though, these symptoms do not last forever and you will soon be seeing the benefits of your new eating style.

3 Simple tips to avoid keto flu!

Before you find yourself dealing with any of these keto flu symptoms, there are a number of things that you can do to help to prevent keto flu. These include:

  1. Start slowly. Don’t just make a harsh change in your diet and leave it at that. Start slowly. For the first couple of days, start with a typical low-carb diet. Get your body used to lower carbs before you restrict them to the extent that you do during the keto diet.
  2. Stay hydrated. The most common reason that you develop keto flu is due to dehydration and loss of minerals. Be sure to drink lots of water and add plenty of electrolytes, salts, potassium and magnesium to your diet. Ensuring you are hydrated and have enough salts, minerals and micronutrients is imperative to stop cramps and nausea. When you give up junk food, this may be the number one source of salt in many people’s diet.
  3. Eat more. Your calories being too low in general can also lead to keto flu symptoms. Be sure you aren’t reducing your calorie intake too much. Try not to go low-carb and low-fat. You will not achieve weight loss any faster, but instead, run the risk of weight loss stopping and feeling hungry, irritable and lethargic. When you live the keto lifestyle, remember to increase your intake of healthy fats. Read here for more info.

How to treat keto flu?

If you find yourself already dealing with these symptoms, here are a few things that you can do to ease your discomfort:

  • Electrolytes. Ensure you are getting enough salt and electrolytes. I enjoy using both Himalayan pink salt (which contains an amazing 84 minerals) AND regular iodised table salt – iodine is crucial for a healthy metabolism and it is lacking in so many diets. Sodium and potassium are crucial too. Why not drink bone broth, or enjoy extra bacon. An easy and yummy way to beat keto flu. Many people find taking a magnesium supplement can stop any cramping or discomfort they are experiencing.
  • Drink lots of water. Like I mentioned before, dehydration is a big part of keto flu. Fight it by drinking water and staying hydrated. Many people add a pinch of mineral salts to their water to help with the cramps and nausea.
  • Eat some clean carbs. Go ahead and add in some clean, healthy, nutrient dense carbs to your diet to help combat keto flu. For example, add in extra non-starchy vegetables, extra nuts and seeds, a few low-sugar berries. OK so you may go over your carb limit temporarily, but it may just help ease keto flu to allow you to continue in the long term.
  • Exercise. If you feel like you can do it, you might try some light exercise. Some people have found that exercise helps your body become more metabolically flexible, and eases the symptoms.

So, yes keto flu is a real thing, and if you find yourself dealing with it, you can expect to experience these symptoms only for a few days, or up to a week.

What can we learn from the keto flu?

If giving up carbs is tough, just imagine what a stronghold carbs are having on your body – and this “carb withdrawal” may be a necessary evil to go through to serve as a reminder to never go back to your old ways of eating.

It’s yet another reason to stop eating and drinking the addictive junk carbs and sugar.

So now you know what is keto flu and how to avoid it, do you feel more prepared to deal with it?

How do you deal with keto flu?

What did you do to fight the keto flu? How long did you experience it – or did you breeze through the induction/starting phase without a hitch?

If you want to get started living keto or low-carb today, why not get the Low-Carb Starter Pack? The complete beginners’ guide with recipes, meal planner, how-to guides and even a measurement tracker.

Would you like some daily help and support? Why not join my FREE Low-Carb Support Group. I’ll see you there.

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Your Definitive Guide to Conquering the Keto Flu

  • The keto flu is your body’s natural response to carbohydrate restriction.
  • Its symptoms include: brain fog, headache, chills, sore throat, digestive issues, dizziness, insomnia, irritability, and more.
  • Symptoms typically last from a few days to two weeks, and up to a month at most.
  • Metabolic flexibility, meaning your ability to adapt to different fuel sources (sans uncomfortable symptoms), dictates the severity of symptoms.
  • Keto flu remedies include: proper hydration; bone broth; electrolytes like potassium, magnesium, and sodium; eating more good fat like MCTs; rest and sleep; mild exercise or meditation; activated charcoal; exogenous ketone supplements; and in some cases, eating more carbs.

You started the keto diet and are just not feeling it. Instead of all those amazing ketogenic benefits you’ve heard about – supreme fat burn, increased energy, keto clarity, and a vibrant sense of well-being – you are irritable at the breakfast table, dizzy all day, and not sleeping at night. The culprit of this miserable feeling? Oh, right: the keto flu. It’s a natural reaction your body undergoes as it switches from burning sugar to fat for energy. In order to get from here to there, your body needs to make a few modifications to the way it runs.

Read on to learn what’s in store as you rev up your internal engine, keto-style.

View keto flu remedies

What is the keto flu?

Barebones – the keto flu is your body’s natural response to carbohydrate restriction. If you’ve embarked on the keto path, you likely know that a keto diet – high in fat, moderate in protein, and low in carbs – implies you burn fatty acids for energy instead of glucose, which comes from sugar and other carbohydrates. While fat is typically a backup fuel source, you will tap into it if there is insufficient glucose, your body’s preferred fuel, from your diet. The metabolic state of ketosis is a fancy word for burning fat rather than carbs, and it is the secret weight-loss weapon to the keto diet.

What are the symptoms of keto flu?

  • Brain fog
  • Headache
  • Chills
  • Sore throat
  • Confusion
  • Dizziness
  • Insomnia
  • Irritability
  • Muscle soreness
  • Nausea
  • Poor focus
  • Stomach pains
  • Sugar cravings

How long does the keto flu last?

The keto flu, aka carb withdrawal, generally kicks in at the 24- to 48-hour mark. Symptoms typically last from a few days to two weeks, and up to a month at most. Whether you experience its symptoms – and to what extent – depends upon your metabolic flexibility, meaning your ability to adapt to different fuel sources (sans uncomfortable symptoms).

Metabolic flexibility is influenced by genetics as well as lifestyle habits. For instance, how you ate prior to going keto may predict the severity your flu symptoms. If you ate a diet low in refined sugar and starches, you’ll likely experience only mild symptoms. A diet high in sugar and carbs may set you up for greater withdrawal symptoms (especially from the sugar).

What causes the keto flu?

What exactly causes keto flu symptoms? When you restrict carbohydrates, your body must learn how to burn its backup energy source, and in order to do so, changes happen from the cellular to hormonal level.

Specifically, there are three changes that occur when you cut out carbs:

Water and sodium flush: When you consume fewer carbs, insulin levels drop – signaling your kidneys to release sodium from the body. This causes a loss of up to about 10 pounds of water weight as water shuttles sodium out of your body. All of this usually occurs in the first five days. The glycogen loss and low insulin levels cause dizziness, nausea, muscle cramping, headaches, and gastrointestinal issues, like diarrhea and constipation. Do your best to drink plenty of fluids and electrolytes at this point (more on this later) – that’ll alleviate some of these cellular symptoms.

T3 thyroid hormone levels may decrease: T3 is a hormone produced by the thyroid gland. Dietary carbohydrates and thyroid function are closely connected, so when you cut carbs, T3 levels can fall. In conjunction with T4, another thyroid hormone, the two T’s regulate your body’s temperature, metabolism, and heart rate. As your body adjusts to a ketogenic diet, lower hormone levels may leave you with brain fog and fatigue.

Increased cortisol levels: The T3 hormonal change is closely connected to a third hormonal change – higher cortisol levels. A ketogenic diet tells your body that you’re in starvation mode. In an effort to increase energy levels on a carb-restricted diet, your body triggers the release of stress hormones, i.e. cortisol. If you experience irritability and insomnia, that’s a clue that your cortisol levels have jumped. Not to worry: as you adjust to utilizing fat and ketones as a new fuel source, your cortisol levels should fall to their old levels.

7 keto flu remedies

Take heart: if you’re experiencing any discomfort, there are things you can do to minimize your unease and conquer the keto flu. Elevated energy and optimal performance are just on the other side of those symptoms. You got this.

Hydrate all day. Water reigns supreme when it comes to kicking the keto flu, especially if you add some unrefined salt. How much should you drink? To determine the minimum amount you need, use your current body weight and divide it by two. That’s how many ounces you need. For instance, if you weigh 140 pounds, you should aim for 70 ounces of water a day.

Drink bone broth. Any water you can sneak into your diet is a great step to set you up for keto rebound. Bone broth adds a serving of water to your diet and a dose of electrolytes – sodium and potassium – which will offset some of the discomfort you feel at a cellular level. Get our bone broth recipe here.

Supplement with electrolytes. “Keto acts as a natural diuretic, so to counteract that you have to make sure you’re giving your body extra sodium,” Suzanne Ryan, best-selling author of “Simply Keto” explains. Replenishing your electrolytes is a great way to start feeling better fast. Take note of the key players – potassium, magnesium, and sodium. If you aren’t getting enough of them from your diet, which can be difficult to do on low-carb, incorporate them by way of supplements.

  • Potassium: Eat fish, meat, leafy greens, winter squash or supplement with 1,000-3,500 mg per day. If you are battling cramps, constipation, or muscle weakness, go for potassium.
  • Magnesium: Eat spinach, chicken, beef, fish or supplement with 300-500 mg per day. Magnesium helps with keto flu symptoms like muscle cramps, dizziness, and fatigue.
  • Sodium: Particularly important if you are exercising or live in a hot climate, supplement with 5,000-7,000 mg per day. Cramping is alleviated with proper sodium intake

Eat more fat – especially MCTs. Upping your fat consumption can speed up your adaptation phase – you’ll start to burn fat instead of glucose more quickly. There is one issue, though. Most fats have to pass through your lymphatic system to your heart, muscles and fat cells before they reach the liver. Only there can they be turned into ketones for the body to use as fuel. MCT oil is different in that it goes straight to the liver after digestion – just like carbs – so they can be used immediately. Supplementing with MCT oil may even help you avoid keto flu altogether. Other easy ways to ramp up the fat: Add coconut oil to your morning brew, try grass-fed jerky or eggs as a snack, and check out some of these recipes to tap the fat.

Get good rest. A sound night’s sleep is a very good thing when it comes to conquering keto flu. It keeps your cortisol levels in check, which will likely lessen your flu symptoms. Aim for 7-9 hours a night, and try these sleep hacks to reach for better zzz’s.

Exercise (mildly) and meditate. Did you note the second word – mild. Yes, mild. The goal here is to reduce cortisol levels (especially initially), so anything that relieves stress will help you. Yoga or gentle walks can do the trick. If exercise isn’t your thing, try meditating. Bottom line, it’s probably best not to go full-on in the gym until you adjust to the keto diet.

Take activated charcoal. Activated charcoal works to detox your body of any toxins. Charcoal binds to chemicals whose molecules have positive charges, including many toxic molds, BPA, and pesticides. As you adapt to burning fat for fuel, you’ll shed extra body fat. Toxins are stored in this fat, so the charcoal assists to swiftly usher these out the door and optimize your general sense of well-being.

Take an exogenous ketone supplement. Exogenous ketones aid with fatigue and boost energy levels by raising the ketone levels in your blood. Note that they are not a replacement for a proper keto diet, though they may help you take it up a notch – especially on the flu. If you choose to go this route, aim for smaller doses of your supplement – spread throughout the day, for the first 3-5 days of the keto flu.

If all else fails, up your carb intake. For some people, increasing fat simply won’t curb keto flu symptoms. If this is the case – and you tested your limits by adding more fat and are still experiencing flu-like symptoms – you’ll want to up your carb intake just a bit. This carb refeeding time goes a long way to ensure you feel better – as it gives your body the chance to adjust to burning fat, because it has some glucose (carbs) to utilize as you adjust.

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The Keto Flu: Symptoms and How to Get Rid of It

The keto flu can make you feel miserable.

Luckily, there are ways to reduce its flu-like symptoms and help your body get through the transition period more easily.

Stay Hydrated

Drinking enough water is necessary for optimal health and can also help reduce symptoms.

A keto diet can cause you to rapidly shed water stores, increasing the risk of dehydration (5).

This is because glycogen, the stored form of carbohydrates, binds to water in the body. When dietary carbohydrates are reduced, glycogen levels plummet and water is excreted from the body (6).

Staying hydrated can help with symptoms like fatigue and muscle cramping (7).

Replacing fluids is especially important when you are experiencing keto-flu-associated diarrhea, which can cause additional fluid loss (8).

Avoid Strenuous Exercise

While exercise is important for staying healthy and keeping body weight in check, strenuous exercise should be avoided when experiencing keto-flu symptoms.

Fatigue, muscle cramps and stomach discomfort are common in the first week of following a ketogenic diet, so it may be a good idea to give your body a rest.

Activities like intense biking, running, weight lifting and strenuous workouts may have to be put on the back burner while your system adapts to new fuel sources.

While these types of exercise should be avoided if you are experiencing the keto flu, light activities like walking, yoga or leisurely biking may improve symptoms.

Replace Electrolytes

Replacing dietary electrolytes may help reduce keto-flu symptoms.

When following a ketogenic diet, levels of insulin, an important hormone that helps the body absorb glucose from the bloodstream, decrease.

When insulin levels decrease, the kidneys release excess sodium from the body (9).

What’s more, the keto diet restricts many foods that are high in potassium, including fruits, beans and starchy vegetables.

Getting adequate amounts of these important nutrients is an excellent way to power through the adaptation period of the diet.

Salting food to taste and including potassium-rich, keto-friendly foods like green leafy vegetables and avocados are an excellent way to ensure you are maintaining a healthy balance of electrolytes.

These foods are also high in magnesium, which may help reduce muscle cramps, sleep issues and headaches (10).

Get Adequate Sleep

Fatigue and irritability are common complaints of people who are adapting to a ketogenic diet.

Lack of sleep causes levels of the stress hormone cortisol to rise in the body, which can negatively impact mood and make keto-flu symptoms worse (11, 12).

If you are having a difficult time falling or staying asleep, try one of the following tips:

  • Reduce caffeine intake: Caffeine is a stimulant that may negatively impact sleep. If you drink caffeinated beverages, only do so in the morning so your sleep is not affected (13).
  • Cut out ambient light: Shut off cell phones, computers and televisions in the bedroom to create a dark environment and promote restful sleep (14).
  • Take a bath: Adding Epsom salt or lavender essential oil to your bath is a relaxing way to wind down and get ready for sleep (15).
  • Get up early: Waking at the same time every day and avoiding oversleeping may help normalize your sleep patterns and improve sleep quality over time (16).

Make Sure You Are Eating Enough Fat (and Carbs)

Transitioning to a very low-carb diet can cause you to crave foods that are restricted on the ketogenic diet, such as cookies, bread, pasta and bagels.

However, eating enough fat, the primary fuel source on the ketogenic diet, will help reduce cravings and keep you feeling satisfied.

In fact, research shows that low-carb diets help reduce cravings for sweets and high-carb foods (17).

Those having a difficult time adapting to the ketogenic diet may have to eliminate carbohydrates gradually, rather than all at once.

Slowly cutting back on carbs, while increasing fat and protein in your diet, may help make the transition smoother and decrease keto-flu symptoms.

Summary You can combat the keto flu by staying hydrated, replacing electrolytes, getting plenty of sleep, avoiding strenuous activities, eating enough fat and cutting out carbs slowly over time.

7 Ways To Prevent Keto Flu

Have you ever started a ketogenic or low-carb diet only to find that you feel sluggish and brain fogged? What happened to the promise of rapid weight loss, mental clarity, and endless energy?

Well you may have encountered Keto Flu. This article covers how to identify it and 7 ways to prevent keto flu so you can reap the full benefits of a ketogenic diet.

The experience of keto flu is often discouraging and can lead many people to fall off their nutrition plan completely. Due to a number of physiological changes that occur during the initial stages of a lower-carb diet, some people experience sluggishness, intense cravings, and many other flu-like symptoms.

When many people think that maybe their body just doesn’t respond well to a ketogenic diet, there are typically three underlying causes: hypoglycemia, HPA Axis Dysfunction, and electrolyte imbalance.

By addressing these three underlying causes, keto flu can be significantly reduced to improve your keto adaptation process and get you on your way to becoming a fat-burning machine!

Keto Adaptation and Keto Flu

Most people beginning a ketogenic diet have been primarily burning sugar for energy their entire lives. When they all of a sudden stop consuming carbs, the body must then relearn how to burn fat for energy.

Hypoglycemia occurs because the body quickly burns through stored sugars and hasn’t yet learned to burn fat, leaving you with an energy deficit (don’t worry it is temporary!)

HPA Axis Dysfunction occurs because sudden drops in blood sugar will tend to promote cortisol release (cortisol raises blood sugar). If this happens too much, then your stress response can become dysregulated and stable blood sugar becomes harder to attain.

Electrolyte Imbalance occurs due to a drop in insulin levels. When insulin drops (due to low blood sugar) you naturally excrete more sodium and minerals in your urine. Because these electrolytes and minerals are important for proper nerve conductivity, this can leave you feeling sluggish and brain fogged.

Strategies To Prevent Keto Flu

The good news is that these keto flu symptoms only last 1-2 weeks on average. After you become adapted to burning fat you will likely experience sustainable weight loss, tons of energy, and mental clarity like never before.

Because the short adaptation period can be such a struggle for some people, it can be hard to get over the hump. These are my top 7 strategies to make sure keto flu doesn’t happen to you.

Back Off Carbs Slowly

While depriving your body of sugar sources is the quickest way to get into ketosis, the side effects can hinder long term success. If you slowly reduce your carb intake while increasing your fat intake, you can smooth your transition to ketosis.

Once you convert yourself to around 70% of calories from fat sources, see how you feel. If you still feel sluggish, try eating more frequently to stabilize blood sugar. I go over how to gradually reduce carbs in the image below and in greater detail in this article.

Increase Your Fat Intake

When you cut out carbs, you are going to need to make sure you are still getting adequate calories from fats. This will ensure your body has what it needs to continue making energy.

You can also try adding in MCT oil to your daily intake to help provide your body with an easy to convert source of ketones. While turning more complex fats into energy can take some adaptation rom the body, MCT oil is more easily converted into ketones. You can learn all about the benefits of MCT oil in this article.

Adding supplemental MCT oil can be a life saver during the initial phases of a ketogenic diet. Start with a Tablespoon in your morning shake or drizzled over your breakfast and progress to using it in more of your meals after about a week to allow your body to acclimate to this concentrated oil.

Additionally, you want to build your meals around healthy fat sources such as avocados, olives or olive oil, coconut oil or coconut milk and grass-fed butter. Here is a list of great fats to use in addition to MCT oil.

Increase Salt & Mineral Intake To Avoid Keto Flu

As I mentioned before, when you become keto adapted, insulin drops significantly. This makes sense because you don’t have any sugar in your blood that insulin needs to carry into the cells. When insulin is low, your body naturally excretes higher amounts of sodium and other minerals.

Supplementing with a high quality multi-mineral, using plenty of sea salt, and sipping on organic broth throughout the day are all great strategies to help combat this keto flu symptom.

Hydrate Well

When your body excretes more sodium (as mentioned above) you naturally retain less water in your body. In order to remain properly hydrated, you need to increase your intake of water and other hydrating beverages.

Organic chicken broth or bone broth are both great for providing minerals as well as water into the system to keep you properly hydrated. Otherwise, adding a pinch of Himalayan sea salt and a squeeze of lemon to your water is also a great option.

Get Some Exercise

Some research suggests that being physically active can improve your ability to switch between fuel sources in the body (1). This makes sense because when you are exercising and you burn up your available sugar stores, you need to quickly convert to another source to sustain energy.

Try going for a brief 15-20 minute jog with intermittent sprints of 20-30 seconds followed by 2 minutes of recovery. Another option is to engage in a HIIT style resistance workout. Use your best judgment here though, if you are really not feeling up to it, then stick to the other strategies in this article. A simple 15-minute walk outdoors can also be helpful!

This type of short duration, high intensity exercise will also increase the production of mitochondria in your cells. Mitochondria produce energy for your body so having a lot of them and keeping them healthy is critical to overall wellbeing.

Don’t Stress

If you are feeling discouraged by your keto flu symptoms, try not to stress over it. Stick to these strategies and know that huge benefits lie just a few weeks ahead (maybe even sooner)! Becoming overly stressed will only hinder your adaptation by increasing cortisol and throwing off you blood sugar balance.

When you begin to feel stressed take a moment, grab some water (or broth), and give yourself some time to pray or meditate. Know that this is temporary and that it was expected from the beginning. It is part of the process and you will overcome and become stronger.

If All Else Fails.. Increase Carb Intake

If you try the strategies above and you are simply feeling like you are not adapting to a ketogenic diet, your body may need more time. Try cycling carbohydrates from clean, nutritious sources like sweet potatoes or a handful of blueberries once a day.

This means you will still be consuming a high fat, low carb diet most of the day. However, once a day have a meal with a healthy portion of carbs. After trying this out for a few weeks, retry a full ketogenic diet and see if your body responds differently.

Keto Flu Summary

When it comes down to it, becoming ketogenic is an adaptation for most people. Adaptations are stressful for the body and so it must be prepared and strategically supported for optimal chances of success.

By using these strategies to control the underlying causes of keto flu symptoms, you also improve your body’s ability to adapt to a ketogenic diet. You can do this! Check out our entire Navigating the Ketogenic Diet online program here

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What Is the Keto Flu and How Do You Cure it?

The keto flu: Yes, it’s a real thing, and it can happen when you drastically and suddenly remove carbs from your diet.

Also known as the “carb flu,” the keto flu is a natural reaction (almost like a feeling of withdrawal) your body undergoes when switching from burning glucose (sugar) as energy to burning fat instead. In fact, some people say the keto flu symptoms can actually feel similar to withdrawing from an addictive substance.

If you’ve recently switched to the keto diet and you’re feeling drowsy, achy, nauseous, dizzy, and irritable, don’t worry. These symptoms are your body’s natural reaction to removing carbs from your diet, and while it may have you second guessing your keto diet decision, we promise you these keto flu symptoms will pass. Stick with it, and soon you’ll be reaping the energizing, fat-burning rewards that come with ketosis.

In the meantime, there are many things you can do to reduce the symptoms of the keto flu. We’ll tell you exactly which remedies you can start using today, but first, let’s take a quick look at why the keto flu happens when you go low carb.

Why The Keto Flu Happens

By default, your body burns glucose (carbs) as its primary energy source, but when you switch to an extremely low carb diet, your body will begin to burn fatty acids for energy instead. Fat is your body’s secondary or “backup” fuel source, which can only be tapped when there’s not enough glucose in your diet. When your body begins burning fat as fuel instead of carbs, you’ve entered the metabolic state known as ketosis (1).

This manipulation of your metabolism yields endless health benefits, and is the whole premise behind the ketogenic diet. If you’d like to learn more, we go into much more detail about ketosis and how it works in our Ketogenic Diet Mastery Guide.

Here’s a list of symptoms that you may experience during the initial transition to the low carb ketogenic diet:

  • Sugar cravings
  • Dizziness
  • Brain fog
  • Irritability
  • Poor focus and concentration
  • Stomach pains
  • Nausea
  • Cramping
  • Confusion
  • Muscle soreness
  • Difficulty falling asleep

How Long Does the Keto Flu Last?

For the average person, the keto flu lasts a week or less, and symptoms usually begin within the first day or two of removing carbs. In extreme cases, the keto flu can last up to a month, but that’s not as common.

If you’re used to eating a diet high in refined sugar and processed foods, you’re more likely to experience the “withdrawal” symptoms of removing carbs. Studies show that sugar is more addictive than certain drugs (2).

If your diet is relatively low in processed sugars and starches, you may only encounter mild keto flu symptoms, or none at all.

Not everyone experiences the keto flu, even when switching from diets high in carbs and sugar. Whether or not you experience the keto flu can depend on your genetics. Some people are naturally metabolically flexible, which means they can shift metabolic states easily without experiencing health symptoms.

However, if you are experiencing the effects of the keto flu, here’s what you can do to reduce your symptoms (and how to prevent symptoms if you’re currently considering going low carb).

How to Manage Keto Flu Symptoms

1. Take an Electrolyte Supplement

When you switch to an extremely low carb ketogenic diet, you end up cutting out some of the richest natural sources of electrolytes, such as starchy fruit and vegetables.

Not getting enough electrolytes in your diet can lead to fatigue, irritability, dizziness, muscle cramping, and cognitive symptoms such as confusion (3)(4). Low electrolytes play a big role in the onset of keto flu symptoms.

One way to get more electrolytes in your diet without kicking your body out of ketosis is to take an electrolyte supplement at least once per day. If you’re active, you’ll also want to make sure you’re taking electrolytes after you work out to prevent muscle cramps and dehydration.

You’ll want to make sure your electrolyte supplement is keto friendly, meaning it has no sugar or artificial sweeteners added (zero calorie sweeteners like stevia and xylitol are fine). Look for an electrolyte supplement that contains sodium, potassium, calcium, and magnesium.

As for electrolyte sports drinks, they typically contain processed sugar in some form, like glucose syrup or high fructose corn syrup. Avoid these by making your own keto-friendly sports drink at home using 1 cup of water, 1 teaspoon of mineral sea salt, and freshly squeezed lemon or lime juice.

2. Hydrate

When you have the keto flu, it’s not only important to make sure you’re getting plenty of electrolytes, but fluids in general.

Staying hydrated will help relieve headaches and boost your energy levels when you’re feeling sluggish. If you forget to drink enough water during the day, setting an alarm on your phone can help you remember, as well as keeping a full glass or bottle of water within reach at all times.

Not sure how much water you need? Follow this simple equation:

Take your current body weight and divide it by two to determine the minimum ounces of water you need (plus extra if you’re active). For example, if you weigh 150 pounds, you need at least 75 ounces of water each day.

3. Drink Bone Broth

Speaking of hydration, meet the ultimate keto flu recovery remedy: bone broth.

Rather than going for the carb-loaded chicken noodle soup (or store-bought chicken broth, which can be high in MSG and other additives), give bone broth a try to help alleviate your symptoms. Bone broth is an easy way to sneak more water into your diet and it also provides electrolytes, such as sodium and potassium.

Both varieties of Kettle and Fire Bone Broth fit into the keto diet macros nicely.

Kettle and Fire Chicken Bone Broth contains 10 grams of protein, 1 gram of fat, and 0 carbs per serving.

Kettle and Fire Beef Bone Broth contains 6 grams of protein, 0 grams of fat, and 2 grams of carbs per serving.

Note: These nutritional values of bone broth are specific to Kettle and Fire. Based on ingredients, the macros can vary for other store bought brands or homemade broth.

4. Eat More Fat

If your carb cravings are so intense, you’ve begun to dream of buttered rolls, donuts, and pasta, do the opposite of what your body is asking for and eat more fat instead.

Yes, ramping up your fat consumption can help speed up the transition of burning fat for fuel instead of glucose. Have a tablespoon of coconut oil in your coffee or tea, snack on half of an avocado and some bacon, and load up on egg yolks at dinner before you reach for the carbs, and remember: the keto flu too shall pass (and the benefits that follow ketosis will be totally worth it in the end).

5. Take an Exogenous Ketone Supplement

Taking an exogenous ketone supplement, such as Perfect Keto can also help reduce keto flu symptoms. Exogenous ketones help fight fatigue and boost energy levels by raising the ketone levels in your blood. To be clear, ketone supplements aren’t a replacement for the keto diet, but they can help you stay in ketosis when you’re meeting your macros, and provide all day energy.

6. Check Your Carb Consumption (You May Need a Few More)

We’ve just told you to eat more fat, but now we’re telling you to eat more carbs? How does that work?

There are two scenarios when you may need to increase your carb intake on the keto diet.

1. High Activity Levels: If you’re extremely active and have keto flu symptoms, adding a few more “clean” carbs to your meals (such as 1/2 cup of sweet potatoes, 1/2 a banana in your protein shake, etc.) can help relieve symptoms in the transition phase.

2. Former Carb-Rich Diet: If the keto flu is hitting you hard and you had a carb rich diet before going keto (especially with processed carbs and sugar), you may need to take a few steps back and eliminate carbs gradually rather than all at once.

Before you add extra carbs to your diet, we recommend going back to step four and increasing fat first. If you experience no relief, do a mini transition phase between your normal diet and going low carb. This gradual transition phase will look different for everyone depending on how many carbs you were consuming on a daily basis.

The best starting point for a transition phase is to eliminate all processed carbs and grains, and focus on getting your carbs only from starchy fruit and vegetables. You can slowly phase out carbs each day by reducing the amount you’re eating at each meal until eventually, carbs will only be 5% of your daily diet, which is when your body can enter ketosis.

7. Gentle Exercise

We get it: the last thing you’re thinking of when you have aching muscles and nausea is going for a brisk jog in the park. But gentle exercise, such as a restorative yoga class, can actually help relieve muscle pain and tension and release endorphins to help boost your mood and motivation.

8. Get Plenty of Restful Sleep

The keto flu affects everyone differently. If you have difficulty falling asleep or getting restful sleep, try these tips to sleep soundly.

Take an epsom salt bath: Soaking in a warm epsom salt bath can help soothe and relax your muscles and improve electrolyte absorption. Magnesium (epsom) salts can be found at any grocery store or health food store.

Drink sleepytime tea: A keto friendly herbal tea with a blend of herbs that promote restful sleep (such as valerian root and chamomile) have a calming effect on your nervous system, and can help promote deeper sleep.

Have an electronics curfew: According to Harvard University, the blue light from tablets, laptops, and smartphones can seriously interfere with your circadian rhythm, and make it difficult for you to fall asleep (6). Having an electronics curfew (ideally at least two hours before you go to bed) is an excellent way to improve your sleep quality. Why not replace the nightly Instagram, Facebook, and email-checking time with a bedtime ritual that helps you relax and unwind?

An epsom salt bath with a cup of keto sleepy time tea is a great starting point. You could also try a guided meditation for relaxation, and a few soothing yoga poses (our favorite is putting your legs up the wall).

The keto flu may be a downside to starting a keto diet, but it’s the only disadvantage. Once your body is used to ketosis, you’ll be amazed at the limitless energy you have, the fat loss you see, and how good you feel on a daily basis.

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If you’ve explored how to start a keto diet, you may be concerned about “the keto flu”, one of the most common side effects of the keto diet. Don’t be! It’s totally avoidable, and temporary if you do experience it.

In this article, I’ll tell you everything you need to know about keto flu and answer all your questions, including:

  • What’s the keto flu?
  • Typical keto flu symptoms and signs of keto flu
  • When keto flu starts
  • How long keto flu lasts
  • What causes keto flu (5 top reasons!)
  • The most important part: 7 effective keto flu remedies and how to avoid keto flu altogether!

What Is Keto Flu?

Keto flu refers to flu-like symptoms that can happen when transitioning into the keto diet. As your body shifts its primary fuel source from glucose and carbohydrates to ketones and fat, it can take your body some time to adjust to this metabolic change.

The keto flu is not actually the flu and is not contagious, but it gets its name because some of the symptoms are similar to the flu.

Unfortunately, the medical community has not formalized exactly what is keto flu (); in fact, PubMed, the library of indexed medical research journals, does not have a single result referring to this phenomenon. But, you can still recognize all the most common symptoms and apply well known keto flu remedies to combat or prevent it.

What Does Keto Flu Feel Like?

The name “keto flu” is somewhat of a misnomer. It’s actually quite different from what you’d experience with an influenza virus.

Although keto flu does cause headaches, dizziness, fatigue, cramps, and muscle pain like the “real” flu might, you should not get a fever, chills, vomiting or respiratory symptoms. If you experience any of these, it’s best to consult with a doctor, as the cause is likely unrelated to a ketogenic diet.

What keto flu feels like and the specific signs of keto flu will vary from person to person, but there are some common ones to watch for.

Signs Of Keto Flu

Your keto flu symptoms may vary, but here are some of the signs of keto flu ():

  • Headache
  • Dizziness
  • Fatigue or tiredness
  • Restlessness or irritability
  • Brain fog or poor concentration
  • Lack of motivation
  • Nausea
  • Insomnia
  • Impaired coordination
  • Sensitivity to heat
  • Sugar cravings
  • Muscle cramps, spasms, weakness or soreness
  • Stomach pain, bloating, constipation or diarrhea

Don’t let this long list scare you! Here is why there isn’t a need to worry about these:

  1. You likely will not get all these keto flu symptoms. Everyone reacts differently.
  2. You can avoid the keto flu! Read on to find out how.

What Causes Keto Flu?

In a nutshell, keto flu happens because your body is adjusting to the new metabolic state of ketosis.

If you’re interested in the science, there are several primary keto flu causes:

Electrolyte imbalance is the primary cause of the keto flu.

Electrolytes are minerals that conduct electricity when dissolved in water and are necessary for critical body functions. The regulate the amount of water in your body, pH levels, moving nutrients into cells, moving waste out of cells, and making sure your nerves, muscles and brain work properly ().

When you restrict carbohydrates, your body produces less insulin, causing your kidneys to flush out excess water and sodium (). In order to maintain the balance between sodium and other electrolytes, your kidneys will also release extra potassium, calcium and magnesium.

Without enough sodium, potassium, calcium, and magnesium in your body, you experience signs of keto flu.

2. Dehydration

When you eat carbohydrates, your body stores the extra as glycogen in the liver, where they are bound to water molecules. Eating low carb depletes this glycogen, which allows you to burn fat – but it also means you are storing less water, making it easier to get dehydrated. ()

The aforementioned effect of reduced insulin increases dehydration further.

However, if you drink a ton of water without replenishing electrolytes, you will dilute the concentration of electrolytes in your body even further and possibly make your keto flu worse. This is why it’s important to address both together.

3. Fuel Source Adjustment

When you eat carbohydrates, your primary fuel source is glucose. When you severely restrict carbs, your body switches to using ketones (from fat) for fuel instead. These are two completely different metabolic processes.

Your body can handle both carbs and fat for fuel, but if you’ve been eating a Standard American Diet (or any high-carb diet) for a long time, it’s likely that your body is more accustomed to glycolysis (breaking down glucose to release energy). So, it may just need a little practice when switching to the new metabolic pathway, ketogenesis (breaking down fat into ketones and using those for energy).

During this adjustment period, you may need to actively seek out a keto flu cure, which is explained below.

4. Sugar Withdrawal

Numerous studies have shown that sugar is highly addictive (, ). If you are used to consuming a lot of sugar, switching to a keto diet can come as a shock and lead to withdrawal symptoms, including cravings, anxiety, depression, irritability, insomnia, cognitive issues, and more.

The effects of sugar withdrawal can compound any keto flu symptoms stemming from electrolyte imbalances, dehydration, etc.

5. Other Deficiencies

In general, switching to a ketogenic lifestyle is a great thing. The healthy fats, low carb vegetables, unprocessed meats, eggs, and other whole foods are nutritionally light years ahead of processed, packaged foods that you may be replacing.

However, just like any diet, you can get the wrong idea. If all you eat is meat, cheese, keto desserts, and low carb bread (as great as they are!), you may end up with deficiencies in vitamins and other micronutrients.

Keto Flu Symptoms And What They Mean

If you’re wondering, “what are the symptoms of keto flu?”, I have the full list above, but I’m also going to break down the symptoms caused by the deficiency of each of the major electrolytes commonly impacted by the keto flu.

Many of these are similar (you need all of them and they work together!), but there are some differences. Still, these lists can help you identify which deficiencies you might have.

Keto Flu Symptoms Caused By Sodium Deficiency

  • Headache
  • Dizziness
  • Fatigue or tiredness
  • Restlessness or irritability
  • Brain fog or poor concentration
  • Lack of motivation
  • Nausea

Keto Flu Symptoms Caused By Magnesium Deficiency

  • Fatigue or tiredness
  • Restlessness or irritability
  • Brain fog or poor concentration
  • Lack of motivation
  • Insomnia
  • Muscle cramps, weakness, spasms or soreness
  • Stomach pain, bloating, constipation or diarrhea

Keto Flu Symptoms Caused By Potassium Deficiency

  • Dizziness or low blood pressure
  • Fatigue or tiredness
  • Nausea
  • Numbness or tingling
  • Heart palpitations
  • Depression
  • Muscle cramps, weakness, spasms or soreness
  • Stomach pain, bloating, or constipation

What Is Keto Flu?:
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Usually, keto flu hits within the first 1-3 days of starting a ketogenic diet.

So even though “how soon does keto flu start?” is one of the most common questions I get about this temporary side effect of keto, the good news is you’ll know pretty quickly if you’re going to get keto flu or not.

How Long Does Keto Flu Last?

On average, the keto flu lasts for about a week. It usually peaks around 3-4 days in.

However, how long keto flu lasts varies from person to person, and can be anywhere from a few days to a few weeks. It should not be longer than that.

Keto flu symptoms will start to dissipate once your body becomes adapted to burning fat for fuel, but there are things you can do to make them go away faster.

Does Everyone Get Keto Flu?

No! Not everyone who starts a keto diet gets the keto flu.

It depends partially on your metabolism (or metabolic flexibility – your ability to switch between carbs and fat for fuel) and genetics, but there are plenty of factors you can control.

In fact, you can avoid keto flu. To do so, you need to understand what causes keto flu (see the section on that above!) and then take steps to prevent keto flu from the beginning (I’ll show you how below!).

Do You Get Keto Flu Every Time You Start Keto?

Hopefully, if you’re starting a keto lifestyle, it will be for the long term. That being said, we’re all human and things happen, so people often ask me whether they’ll experience keto flu again if they re-start after a period of not being in ketosis.

This varies from person to person. Some people become very efficiently fat adapted and don’t get keto flu again if they cheat and then resume keto. This depends on your metabolic flexibility, as mentioned above.

Often times, people restarting keto may experience mild signs of keto flu, but they are not as severe as the first time. Or you might not experience them at all as your metabolic flexibility improves.

I highly recommend that you read my tips below for how to avoid keto flu altogether. Why go through it when you don’t have to? You can avoid keto flu the first time… and every time if you do have a slip-up.

Is Keto Flu Dangerous?

The keto flu is unpleasant, but generally not dangerous. People with kidney issues or low blood pressure may be affected more, due to the diuretic effects of the diet and (temporarily) reduced electrolytes.

Some people think that the keto flu is a sign of ketoacidosis, a life-threatening condition in which excessive ketones build up in the blood. Fortunately, ketosis does not cause ketoacidosis, and despite their similar names, they are completely different. The latter is caused by a prolonged lack of insulin, usually from unmanaged diabetes.

Electrolytes are important for our bodies to function properly, though, so the sooner you can get them in balance, the better.

Keto Flu Symptoms & Remedies:
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Knowing the signs of keto flu is great and all, but if you’re going through it, what you really need to know is how to cure keto flu, right?!

Fortunately, you don’t have to just suffer and deal with it. I’ll show you how to get rid of keto flu quickly – and how to prevent it in the future. You don’t have to go through it just because you’ve decided to follow a keto lifestyle.

I’ve compiled all the best keto flu remedy methods, whether you already have it or just want to avoid keto flu altogether.

Here is how to prevent keto flu from the start:

1. Replenish Electrolytes (The Best Keto Flu Remedy!)

Getting enough electrolytes on a keto diet is the single best thing you can do to beat keto flu.

In general, here is how much of each you need daily:

  • Sodium – 4000-7000 mg per day (that’s 2-3 teaspoons of salt per day!)
  • Magnesium – 300-600 mg per day
  • Potassium – 3000-4700 mg per day

If you’re just starting to look for a keto flu remedy to try, start with electrolytes – and start with getting them from food. Check below for what to eat for keto flu to replenish these electrolytes, as well as supplement options just in case you absolutely need them.

2. Drink Plenty Of Water

As mentioned above, a ketogenic diet causes a lot of water loss in the beginning, which can leave you dehydrated. Ironically, dehydration can actually lead to bloating and water retention, as well as dizziness and fatigue ().

TIP: Keep a bottle of water near you all the times to encourage drinking frequently. I love this bottle that has time markers, so that I can stay on track for the day!

Aim for 16 cups of water per day (a gallon), but listen to your body’s signals and don’t overdo it. The goal is to reempt your thirst.

Don’t forget to replenish electrolytes as you drink water, to avoid diluting their concentration in your body even more.

3. Ease Into Keto Gradually

You don’t have to start keto cold turkey. The keto macro calculator will show you the optimal macros for you on a keto lifestyle, but starting slowly is a great way to avoid keto flu.

  • To ease into keto gradually, start by cutting refined sugar for a few days or a week
  • Next, cut starches (wheat, rice, potatoes, etc.)
  • From there you can progress to a low carb diet (see the comparison of a keto vs low carb diet here), without restricting carbs enough to be in ketosis all the time.
  • Once you feel comfortable eating low carb, progress to a ketogenic diet.

If you are already experiencing symptoms, one keto flu remedy would be to eat some moderate carb, nutrient-dense foods, such as extra vegetables or berries. Even if you go over your carb limit, it’s worth it if it gets you to stick with the lifestyle. You can reduce further once you feel better.

4. Eat Nutrient Dense Foods

Just because you are limiting carbs, that doesn’t mean that’s all there is to it. In addition to macro goals, the goal of the keto lifestyle is to eat clean, whole foods, so that we also get a wide range of micronutrients.

In particular, getting enough (low carb) veggies is absolutely crucial – check the keto food list for ideas!

5. Eat More Fat & Calories

If you are not eating enough, this can cause some symptoms similar to keto flu. Be sure to eat enough that you aren’t hungry. Remember, the primary fuel source on a keto diet is fat, so you need to add enough to keep you satisfied and to help you adapt to burning fat for fuel.

Resist the urge to make your diet both low carb and low-fat, which will just put your body into starvation mode. You’ll be hungry, miserable, and are bound to run into the telltale signs of keto flu.

As you increase fat, watch the type of fat. You may need to watch your medium chain triglycerides (MCT’s), such as coconut oil:

  • If you have abdominal pain, you may need to ease into MCT’s slowly to avoid stomach issues. Balance them out with long chain triglycerides, such as olive oil or avocado oil.
  • If you can handle MCT’s without a problem, try increasing them because they will get you into ketosis faster. (The liver metabolizes them very efficiently.)

6. Exercise (Gently)

If you notice an initial decrease in exercise performance when you start keto, don’t despair. This is temporary and usually resolves itself by week 4 of a keto lifestyle. (, )

Even if you feel tired, don’t skip exercise altogether! Try less intense activities, such as yoga or walking, because these already often use fat as a primary fuel source.

And, exercising can help improve your body’s ability to switch between the metabolic processes for burning fat and sugar, meaning you avoid keto flu ().

7. Sleep More

Sleep is important no matter how you’re eating, but if you’re already fatigued and struggling with keto flu, it becomes even more so. Lack of sleep can increase cortisol levels, which can amplify some of the same keto flu symptoms you’re trying to avoid ().

What To Eat For Keto Flu

I’m a firm believer in using food as a keto flu cure whenever possible. Medications and supplements have their place, but always start with food first to see if that’s enough. Besides, you avoid any risk of overdose this way.

TIP: Don’t bother with sports drinks for replenishing electrolytes. Even if they are sugar-free, they actually have very small amounts of electrolytes compared to the food sources below, and won’t be enough to really make a dent.

Below are my favorite methods for how to treat keto flu with food.

Sodium Rich Foods For Keto Flu

Sodium is the most common electrolyte imbalance involved in the keto flu, and fortunately, it’s the easiest to incorporate into your food.

Daily Sodium Goal: 4000-7000 mg per day

Here are ways to get more sodium from food:

  • Salt – add it to everything! The goal is 4000-7000 mg of sodium per day, which is approximately 2-3 teaspoons of sea salt or table salt daily. This will vary slightly depending on the brand of salt you buy, though, because sodium content varies. If you can, get Himalayan pink salt.

REMINDER: Let go of any lingering “sodium is bad” concerns. Remember, your body is flushing out a lot of it when you eat keto, and depleted sodium is a big part of why you feel bad!

  • Bone broth – This is my favorite brand of bone broth – it tastes like you simmered it at home for hours, and has the same ingredients you’d use at home. A cup has 240mg sodium. Use code WHOLESOME for 10% off!
  • Boullion cubes – Avoid ones with added sugar or MSG. I love these vegetable boullion cubes! Each cube has 2100mg sodium.
  • Bacon – Naturally has plenty of salt added! I like to cook bacon in the oven on the weekend and use in recipes throughout the week. I get my bacon here (use that link to get a FREE package!), so that it’s uncured and sugar-free. One slice of bacon has 137mg sodium.
  • Salted nuts – Try mixed nuts or these portion-controlled macadamia nut packs. A serving will only have 100-120 mg sodium, though, so don’t rely on it as your main source.
  • Pickles + pickle juice – Make sure there is no added sugar! I like this brand or this brand. An ounce of pickles typically has 125 mg sodium.

How To Get More Sodium To Cure Keto Flu:
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Magnesium Rich Foods For Keto Flu

In addition to the more broad keto flu symptoms like headache and fatigue, magnesium is particularly helpful for insomnia, constipation, and cravings.

Daily Magnesium Goal: 300-600 mg per day

Here are some good food sources of magnesium:

  • Seaweed – This is the best source of magnesium from food! A one-ounce serving of dried agar seaweed contains 216 mg magnesium.
  • Seeds – Hemp, flax, pumpkin and chia seeds are all great sources of magnesium. Hemp seeds are at the top (179 mg per ounce) – use them to make keto oatmeal. Pumpkin seeds are also excellent, at 150 mg per ounce.
  • Nuts – Get out that almond flour (and browse my almond flour recipes)! Almonds and brazil nuts have the highest content, about 80 mg magnesium per ounce.
  • Avocados – One of many reasons I love this superfood is it’s packed with magnesium! (See it in my logo?) One avocado contains 58 mg magnesium.
  • Leafy greens – Each cup of raw spinach, kale, or collard greens has approximately 25-30 mg magnesium. It gets a lot more concentrated if you cook them.

How To Get More Magnesium To Treat Keto Flu:
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Potassium Rich Foods For Keto Flu

Potassium has serious side effects if you overdose on it, so a whole foods based approach is best for this electrolyte in particular ().

Daily Potassium Goal: 3500-4700 mg per day

Here are some of the best keto-friendly sources of potassium:

  • Potassium chloride – This is a table salt replacement (instead of sodium chloride), such as this one. Only use this if you already have enough sodium AND you are watching your intake to make sure you don’t go over 4700 mg potassium in a day. Just 1/6 teaspoon has 530 mg potassium, so it adds up fast!
  • Avocados – An avocado has a whopping 974 mg potassium!
  • Bone broth – In particular, this chicken bone broth has 530 mg of potassium per serving.
  • Spinach – A cup of raw spinach has 186 mg potassium, which doesn’t sound like much, but you can easily have a few cups. And if the spinach is cooked, you’ll need much less for the same amount of potassium, since it shrinks so much.
  • Broccoli – Broccoli has 288 mg potassium per cup! My favorite simple way to serve it is sauteed broccoli with garlic.
  • Mushrooms – A cup of raw mushrooms has 223 mg potassium, yet only 1.6 g net carbs.
  • Leafy greens – The amounts vary, but many leafy greens are rich in potassium. For example, just one cup of cooked Swiss chard has 961 mg.
  • Zucchini – One of my fave low carb veggies is also one of the best potassium sources, at 325 mg per cup. Try making zucchini boats or zucchini noodles!
  • Beef or pork – 3 ounces of beef has 270 mg potassium, while the same amount of pork has 360 mg.

How To Get More Potassium To Beat Keto Flu:
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Keto Flu Supplements

Try to get your electrolytes from food sources whenever possible. However, if you find that you can’t get enough, you can add a supplement.

If possible, consult with your doctor before beginning any supplement regimen, especially if you have impaired kidney function.

Electrolyte Blend For Keto Flu

If you want to know what to take for keto flu to see improvements quickly (and food just isn’t cutting it), these are my favorite keto electrolyte supplements specifically designed for a keto diet. They include a balance of sodium, potassium, magnesium, calcium, and chloride, without being so high in any of them that you risk dangerous levels.

Magnesium Supplements For Keto Flu

Often times, sodium and potassium are easy enough to get from foods, but magnesium is more difficult and you need only a magnesium supplement.

Unfortunately, most magnesium supplements are sold as magnesium oxide, which is a laxative and has poor bioavailability (read: we don’t absorb much of it).

Choose one of these magnesium supplements instead:

  • Magnesium glycinate – This form of magnesium contains glycine, which has a calming effect, good bioavailability, and no laxative properties.
  • Magnesium citrate – Magnesium citrate can alleviate constipation and acid indigestion, is inexpensive, and has moderate bioavailability.
  • Magnesium L-threonate – In addition to high bioavailability, this one has been shown to improve memory and cognitive function (). Bonus!
  • Magnesium malate – This form of magnesium has the highest bioavailability ().

Many people have decided to try the ketogenic diet for weight loss. The most recent evidence shows that reducing your carbohydrate intake to a minimum may help you shed a few pounds, at least in the first few weeks to months. However, we don’t really know whether, over the long term, achieving and maintaining ketosis is better for weight loss than other diets. Almost any intervention can cause undesirable consequences, and the ketogenic diet is no different. One of the most well-publicized complications of ketosis is something called “keto flu.”

The so-called keto flu is a group of symptoms that may appear two to seven days after starting a ketogenic diet. Headache, foggy brain, fatigue, irritability, nausea, difficulty sleeping, and constipation are just some of the symptoms of this condition, which is not recognized by medicine. A search for this term yields not a single result on PubMed, the library of indexed medical research journals. On the other hand, an internet search will yield thousands of blogs and articles about keto flu.

It is tricky to describe exactly what happens after the diet change, because we are left with only our own observations and experiences. These symptoms may not even be unique to the ketogenic diet; some of my patients describe similar symptoms after they cut back on processed foods, or decide to follow an elimination or an anti-inflammatory diet.

What causes keto flu?

Well, we don’t really know why some people feel so bad after this dietary change. Is it related to a detox factor? Is it due to a carb withdrawal? Is there an immunologic reaction? Or is this a result of a change in the gut microbiome? Whatever the reason is, it appears the symptoms attributed to the keto flu may happen, not to everyone but to some people, after “cleaning up” their diet.

What to do for keto flu?

If you decide for whatever reason to change your diet and feel tired and a little off, do not become exasperated and lose hope. Here are a few tips:

  • There is no need to go online and buy any expensive supplements. Many websites are trying to make big bucks selling products to make you feel better without any data to back up those claims.
  • Despite its name, this is not like the flu. You will not develop a fever and the symptoms can hardly ever make you incapacitated. If you feel very ill, consider visiting your doctor, as something else may be happening.
  • Make sure you drink plenty of water. Some diets can make you dehydrated.
  • Eat more often and make sure you have plenty of colorful vegetables. Switching from a standard American diet, rich in simple carbs, trans fats, and saturated fat, is a big change in how your cells use energy. Food is not only calories and energy, it is communication to your cells.
  • Do not give up if you are committed to a plan. You may feel exhausted for a few days, but at the end of a week, your energy level will most likely return to normal and you may feel even better.
  • If everything else fails, consider easing into the new diet more slowly, instead of “cold turkey.”

Undesirable symptoms may show up in the first few days after changing what you eat. But this should not be the deciding factor when choosing what to put on your plate. Ideally, you should have the most comprehensive and nutritionally dense diet possible, and the Mediterranean and DASH diets have the best evidence to support living a long and healthy life.

One of the most common side effects of transitioning into a low-carb, ketogenic diet is the dreaded keto headache (also called a low-carb headache). But don’t let the flu-like side effects in the first week or two discourage you from your ketogenic journey.

There are specific lifestyle hacks and nutrient protocols you can take to prevent headaches induced by suddenly reducing your carbohydrate intake.

Eventually, your body will adapt to using fats as energy and the symptoms will disappear.

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Read on to explore the reasons you might experience a keto headache and the steps you can take to prevent it as you reap the powerful health benefits of ketosis.

What Happens to Your Body When You First Go Keto

You’ve probably spent a good portion of your life feeding your body large amounts of carbohydrates, many of them from processed food sources.

This means your cells, hormones, and brain have adapted to using carbohydrates as their main source of energy.

Transitioning to a fat-dominant fuel source will confuse your body’s metabolism in the beginning.

This metabolic confusion will put your body through an “induction phase.”

This is the time when your metabolism works overtime to get accustomed to using ketones for energy (from fats) rather than glucose (from carbohydrates).

During this phase, you may experience flu-like symptoms commonly referred to as the “keto flu” — especially headaches and brain fog — because your body is going through physical carb withdrawal.

Mental Fog Is Normal at the Start of Keto

One of the very first signs of this “induction phase” comes from your brain losing its main source of fuel — glucose.

If you’ve never followed a low-carb, high-fat diet, your brain has been using carbohydrates as its main energy source.

When you start increasing your fats and restricting carbs, your body starts to burn through its last stores of glycogen. At first, your brain won’t know where to find the energy it needs because of the lack of carbohydrates.

It’s normal to start staring off into space, experiencing headaches, and feeling irritable.

A good way to combat these symptoms is to go as low-carb as possible when you’re first starting out. This way your body is forced to use up all of its glycogen stores much faster.

Many people try to taper off their high carb intake over time, but doing so will only make the brain fog last longer.

When you get into a state of ketosis, a large portion of the brain begins to burn ketones instead of glucose. It can take a few days or up to a couple of weeks for the transition to happen.

Luckily, ketones are a highly potent fuel source for the brain. Once your brain gets accustomed to using fats as energy, brain function is optimized.

Many studies have shown long-term ketogenic dieters to have improved brain cognition. The keto diet has even been considered for treating brain conditions such as memory loss.

The Keto Induction Phase Is Stressful on Your Body

Without much sugar from carbohydrates present, your body will begin to decrease blood sugar levels and increase the production of the stress hormone, cortisol.

Cortisol is a glucocorticoid hormone released by your adrenals to make sure your energy level is sufficient to survive. When you have low blood sugar levels, your brain sends a signal to your adrenals to release cortisol. Your body will begin to burn glycogen (stored glucose) for fuel.

Carbohydrate restriction — and thus, the keto diet — may sound like a bad idea due to your increased body stress triggering the release of additional cortisol. But this isn’t the case. Over time, your body will adapt and develop a preference for using fat as fuel through ketosis.

One study tested three separate diets: a low-carb diet, a low-fat diet, and a low-glycemic diet. This study showed that the different diets had significantly different metabolic effects, with the low-carbohydrate diet proving to be the most effective.

Causes of Keto Headache

One of the most common symptoms when making sweeping dietary changes, like the keto diet, is the pounding headache that accompanies carbohydrate restriction.

When your body’s been running on high-carb foods like bread and starchy vegetables your whole life, making a large transition to burning fat as fuel will require an adjustment period.

Keto headache is just one keto flu symptom and shouldn’t be compared to the normal flu. The keto flu isn’t viral or contagious and you’re not sick — you’re adapting.

What Causes a Keto Headache?

There are three main reasons why you may develop a headache after going low-carb: dehydration, electrolyte imbalances, and carbohydrate or sugar withdrawal.

The typical Western diet contains large amounts of sugar which give your body an instant rush.

Sugar impacts your brain through the same reward system that is seen with equally addictive substances, like cocaine, which is why you experience symptoms similar to drug withdrawals.

In fact, it’s the “sugar high” that’s responsible for your increased sugar cravings. The more sugar you eat, the more you want.

How Long Does the Keto Headache Last?

Some people may not experience any withdrawal symptoms at all. Everyone is different and the length of the symptoms depends on several factors.

For example, if you followed a diet relatively low in carbs before going keto and ate large amounts of green vegetables (or took a high-quality greens supplement), there’s a chance that your symptoms would be very short-lived or even nonexistent.

On average, the keto headache will last anywhere from 24 hours to one week.

In rare cases, it can take up to 15 days for the symptoms to subside.

Some people prefer to start keto on the weekend so the symptoms are more tolerable and won’t affect everyday life too much.

Dehydration Is Common During the Keto Induction Phase

When you adopt a low-carb high-fat ketogenic lifestyle, your body begins to excrete excess water.

Don’t get too excited when you notice a lot of weight loss after first beginning keto. The bodyweight reduction isn’t all from fat loss; it’s water being flushed out of your body.

Ketosis is known for its strong diuretic effect. This means your body is excreting both water and electrolytes which leads to reduced water retention.

Water is stored in your body from carbohydrates. When you restrict carbohydrates, your body begins to excrete water rapidly.

For each gram of glycogen (from carbs) used as energy, twice the mass is lost in water.

Once your body enters ketosis, your body starts sparing glucose but water loss continues. Having ketones present in your body will lead to more water excretion.

It’s vital to drink plenty of water while adapting to carbohydrate restriction in order to mitigate dehydration symptoms and maintain your overall health and well-being.

Electrolyte Imbalances Are Common When You First Go Keto

The main electrolytes to keep a close eye on are magnesium, sodium, and potassium.

When your body excretes water, you begin to flush out these essential electrolytes which are crucial for several different bodily functions like energy production, body temperature control, and optimal brain function.

Your daily electrolyte requirements are higher on keto compared to a normal diet.

An electrolyte supplement can help while you’re in transition.

Sodium Requirements

Insulin plays a huge role in electrolyte maintenance. It’s a hormone that lowers your blood sugar when it’s too high.

The main job of insulin is to shuttle sugar into cells so they can use it as fuel and deposit excess sugar into fat. It also works to promote sodium absorption in the kidneys.

When you start a low-carbohydrate diet, insulin levels are much lower.

The sodium eventually draws more fluid into your kidneys to prepare for the excretion of water.

Less insulin in the body means there is less sodium present.

Low sodium levels in your body are one of the main reasons why you may experience decreased energy levels and headaches while on a low-carb diet.

You should aim for 5,000 to 7,000 mg of sodium throughout the day.

This can be consumed in the form of pink Himalayan sea salt, bouillon, bone broth, and even sodium pills.

Potassium Requirements

If you are potassium-deficient, you can expect to experience depression, irritability, constipation, skin problems, muscle cramps, and heart palpitations

To combat this you should consume ~3,000 mg of potassium a day.

Here is a list of keto-friendly foods that contain ample amounts of potassium:

  • Nuts: ~100-300 mg per one oz serving
  • Avocados: ~1,000 mg per serving
  • Salmon: ~800 mg per serving
  • Mushrooms: ~100-200 mg per serving

It’s important to note that too much potassium can be dangerous. While it would be difficult to reach the upper threshold of toxic levels, it’s best to steer away from potassium supplements and stick to the natural sources listed above.

Magnesium Requirements

While magnesium deficiency is not as common for low-carb dieters, it’s important to maintain optimal levels.

A magnesium deficiency can lead to muscle cramps, dizziness, and keto headache.

The recommended daily average for people on the keto diet is ~400 mg of magnesium a day.

Try these keto-approved, magnesium-rich foods:

  • Cooked spinach: ~75 mg per cup
  • Cacao powder with dark chocolate: ~80 mg per one tbsp of cacao powder
  • Almonds: ~75 mg per 1 oz
  • Salmon: ~60 mg per fillet

How to Prevent a Keto Headache

The headache you get when adapting to burning fat for fuel comes from an impaired ability to effectively use fat as energy.

Any time your body’s ability to burn fat is impaired, you have a hard time losing weight. You become very hungry when your blood sugar runs out — no matter how much fat you have available to burn.

To combat the keto headache, you must improve your body’s metabolic flexibility to burn fat as energy instead of glucose.

Metabolic flexibility is your capacity to adapt fuel oxidation to fuel availability. This is your body’s ability to switch from one fuel source to another (from carbohydrates to fat).

Your keto headache symptoms will soon diminish once you become used to using fat (ketones) as energy.

Here are five techniques you can implement today to prevent keto headache:

#1. Drink Water and Salt

When you start eating a low-carb diet, your insulin levels will naturally go down. You won’t hold onto as much sodium as compared to a traditional Western diet with a moderate amount of carbs.

You also begin to excrete stored water when you restrict carbohydrates.

Sodium deficiency is one of the main causes of keto headache and can be mitigated by adding more water and salt into your system.

It’s important to increase the amount of salt you consume because drinking more water will flush out sodium at the same time.

Consuming bouillon or bone broth will help you maintain proper amounts of sodium.

If you are still having difficulty increasing your salt intake on a low-carb diet, supplementing with sodium supplements and simply adding more salt to every meal will help.

#2. Eat More Fats

Eating more dietary fat will help your body get accustomed to using fats as energy. Since you’re replacing carbs with fats as your main source of calories, you need to consume larger amounts of fat than you were previously.

You should aim for 65-70% of your total calories from fats.

Taking the time to track your fat intake should be a priority in the beginning since it’s very easy to undereat fats. This is because fats are more calorically dense and will fill you up quicker.

Eat fatty meats like rib-eye steak, bacon, salmon and chicken thighs. Add coconut oil and butter to each meal to increase your fat intake.

#3. Take Supplements

Supplements can greatly help your conversion into a fat-fueled machine, but it’s important to never use supplements as a replacement for dietary deficiencies.

Some key vitamins and minerals that can help mitigate a keto headache include:

  • L-carnitine: High fat intake from the keto diet means more fatty acids need to be moved into the mitochondria for fat oxidation. Carnitine is required for effective transportation.
  • Co-Enzyme Q10: This is an antioxidant responsible for the cellular process of creating energy. It’s another supplement that helps mobilize fat and will help you transition into ketosis faster.
  • Omega-3 fatty acids: Fish oil is a potent natural anti-inflammatory. Consuming omega-3’s will also help to lower triglyceride levels in your body which are fat molecules held in the blood for later use.

#4. Exercise More

Studies have shown that exercise can improve your body’s metabolic flexibility.

Exercising increases both fat utilization and improves weight loss, both are contributing factors to combating the dreaded keto headache.

One study shows that the benefits of exercise go beyond weight loss. It also helps to repair broken metabolisms. This study showed that after exercise, the metabolism of people with type 2 diabetes was restored and they were able to utilize calories for energy more efficiently.

Making a habit to work out will help you regain your metabolic flexibility and stimulates your body to increase fat burning both during exercise and at rest.

Exercise will greatly improve the speed at which your body starts using fat as its main source of energy and will help mitigate symptoms of keto headache.

#5. Supplement With Exogenous Ketones

Taking exogenous ketones is an effective way to elevate your ketone levels, even if you haven’t fully converted to using fats as a primary source of energy. They can elevate your beta-hydroxybutyrate (BHB) levels by up to 2 mMol after consumption.

Exogenous ketones cause blood glucose to decrease due to an increase in insulin sensitivity. This is important during the induction phase because you’re priming your body to start preferring fats as energy rather than carbohydrates.

They also contain ample amounts of calcium, magnesium, and sodium which are critical electrolytes your body needs for peak brain and body functioning.

By adding exogenous ketones into your routine, you will drastically mitigate the severity of your keto-induced headaches.

Don’t Be Discouraged by the Keto Headache

While the keto headache may sound daunting and may discourage you from adopting a keto diet, taking the steps to mitigate the symptoms isn’t as hard as some make it out to be.

Replacing essential nutrients and minerals, exercising frequently, and maintaining a proper low-carb, high-fat diet will ensure that your keto flu-like symptoms diminish sooner than later.

Remember that a low-carb headache is a normal induction stage of the process and happens to most people who adopt this way of eating.

The light at the end of the tunnel is much closer than you think. Let this encourage you to stick it out until you begin to experience the benefits of a low-carb, high-fat ketogenic lifestyle. It will all be worth it!

7 Dangers of Going Keto

The ketogenic diet—also known as the “keto diet” or just “keto”—has become the latest big thing in weight-loss plans, touted recently by celebs like Jenna Jameson, Mama June, and Halle Berry. The diet involves cutting way back on carbohydrates, to 50 grams a day or less, to help the body achieve a state of ketosis, in which it has to burn fat (rather than sugar) for energy.

Doctors say that the keto diet can be helpful in treating epilepsy; it’s unclear exactly why, but something about a ketogenic state seems to reduce the frequency of seizures. Animal studies have also suggested that the diet may have anti-aging, anti-inflammatory, and cancer-fighting benefits, as well.

RELATED: Jillian Michaels Slams the Keto Diet: ‘Why Would Anyone Think This Is a Good Idea?’

But as a general weight-loss plan, keto is more controversial. Some health experts warn against it entirely, citing unpleasant side effects, health risks, and the diet’s unsustainable nature. Even many keto diet proponents admit that, if the diet’s not done “the right way,” it can be the opposite of healthy.

Here are a few things you should know about the ketogenic diet before you try it as a way to lose weight. Yes, you might drop pounds, but you should also watch out for the following side effects or complications.

RELATED: Jillian Michaels Isn’t the Only One Who Hates Keto—These 5 Other Experts Say Ditch the Diet

1. The “keto flu”

“Some people report that when they start ketosis, they just feel sick,” says Kristen Kizer, RD, a nutritionist at Houston Methodist Medical Center. “There can sometimes be vomit, gastrointestinal distress, a lot of fatigue, and lethargy.” This so-called keto flu usually passes after a few days, she adds.

Josh Axe, a doctor of natural medicine and clinical nutritionist, estimates that about 25% of people who try a keto diet experience these symptoms, with fatigue being the most common. “That happens because your body runs out of sugar to burn for energy, and it has to start using fat,” he says. “That transition alone is enough to make your body feel tired for a few days.”

You may be able to minimize the effects of keto flu by drinking plenty of water and getting plenty of sleep. Axe, who sells keto-related supplements on his website, also recommends incorporating natural energy sources to battle fatigue, like matcha green tea, organic coffee, or adaptogenic herbs.

RELATED: Keto Flu Explained: Why Low-Carb Diets Can Make You Feel Sick and Tired

2. Diarrhea

If you find yourself running to the bathroom more often while on a ketogenic diet, a quick internet search will show you that you’re not alone. (Yes, people are tweeting about keto diarrhea.) This may be due to the gallbladder—the organ that produces bile to help break down fat in the diet—feeling “overwhelmed,” says Axe.

Diarrhea can also be due to a lack of fiber in the keto diet, says Kizer, which can happen when someone cuts way back on carbs (like whole-grain bread and pasta) and doesn’t supplement with other fiber-rich foods, like vegetables. It can also be caused by an intolerance to dairy or artificial sweeteners—things you might be eating more of since switching to a high-fat, low-carb lifestyle.

RELATED: 10 Things That Can Cause Diarrhea

3. Reduced athletic performance

Some athletes swear by the ketogenic diet, not just for weight loss but for improved performance in their sport, as well. But Edward Weiss, PhD, associate professor of nutrition and dietetics at Saint Louis University, doesn’t buy it. “I hear cyclists say all the time that they’re faster and better now that they’re on the keto diet, and my first question is, ‘Well, how much weight did you lose?’” he says.

In a recent study in the Journal of Sports Medicine and Physical Fitness, Weiss and his colleagues found that participants performed worse on high-intensity cycling and running tasks after four days on a ketogenic diet, compared to those who’d spent four days on a high-carb diet. Weiss says that the body is in a more acidic state when it’s in ketosis, which may limit its ability to perform at peak levels.

“Just losing a few pounds is enough to give you a huge advantage on the bike, but I’m very concerned that people are attributing the benefits of weight loss to something specific in the ketogenic diet,” Weiss continues. “In reality, the benefits of weight loss could be at least partially canceled out by reductions in performance.”

RELATED: 4 Things You Need to Know Before Trying the Keto Diet

4. Ketoacidosis

If you have type 1 or type 2 diabetes, you shouldn’t follow the keto diet unless you have your doctor’s permission and close supervision, says Kizer. “Ketosis can actually be helpful for people who have hyperglycemia issues, but you have to be very mindful of your blood sugar and check your glucose levels several times a day,” she says.

That’s because, for people with diabetes, ketosis can trigger a dangerous condition called ketoacidosis. This occurs when the body stores up too many ketones—acids produced as a byproduct of burning fat—and the blood becomes too acidic, which can damage the liver, kidneys, and brain. Left untreated, it can be fatal.

Ketoacidosis has also been reported in people without diabetes who were following low-carb diets, although this complication is quite rare. Symptoms of ketoacidosis include a dry mouth, frequent urination, nausea, bad breath, and breathing difficulties; if you experience these while following the keto diet, check in with a doctor right away.

RELATED: Keto Diet Constipation Is a Legit Issue—Here’s How to Deal

5. Weight regain

Because the keto diet is so restrictive, health experts say it’s not an appropriate plan to follow long-term. (Even Axe says it’s best done for 30 to 90 days, followed by a more sustainable diet plan.) But the problem with that, says Kizer, is that most people will regain a lot of the weight they lost as soon as they go back on carbs.

“It’s an issue with any fad diet, but it seems to be extra common with ketosis,” says Kizer. “When people tell me they want to try it because their friends lost weight, I always tell them, ‘Just watch, I almost guarantee that they’ll gain it all back.’”

These types of back-and-forth weight fluctuations can contribute to disordered eating, Kizer says, or can worsen an already unhealthy relationship with food. “I think the keto diet appeals to people who have issues with portion control and with binge eating,” she says. “And in many cases, what they really need is a lifestyle coach or a professional counselor to help them get to the bottom of those issues.”

RELATED: The Best Diets of 2019—and Why the Keto Diet Ranked So Low

6. Less muscle mass, decreased metabolism

Another consequence of keto-related weight changes can be a loss of muscle mass, says Kizer—especially if you’re eating much more fat than protein. “You’ll lose weight, but it might actually be a lot of muscle,” she says, “and because muscle burns more calories than fat, that will affect your metabolism.”

When a person goes off the ketogenic diet and regains much of their original weight, it’s often not in the same proportions, says Kizer: Instead of regaining lean muscle, you’re likely to regain fat. “Now you’re back to your starting weight, but you no longer have the muscle mass to burn the calories that you did before,” she says. “That can have lasting effects on your resting metabolic rate, and on your weight long-term.”

RELATED: 5 Long-Term Health Risks of Going Keto

7. Increased risk of heart disease and diabetes

Axe says that, when done right, the keto diet includes lots of vegetables and lean sources of animal protein. In other words, it’s not an excuse to eat butter and bacon—although some people may try to do just that.

That’s why many health experts are concerned about people on the ketogenic diet, especially those who try it without the guidance of a doctor or nutritionist. Doctors say that high-fat diets like this one may raise cholesterol levels, and some studies suggest that they increase the risk of diabetes. Some have even called it a “cardiologist’s nightmare.”

RELATED: 10 Keto-Friendly Vegetables You Should Eat More Of

Just this week, a 25,000-person study presented at the European Society of Cardiology Congress in Munich suggested that people on the lowest-carb diets had the highest risk of dying from cancer, cardiovascular conditions, and all other causes. Another study, published this month in the Lancet, also found that people who followed diets that were low in carbs and high in animal proteins (typical of the keto diet) had a higher risk of early death compared to those who consumed carbs in moderation. (The opposite was true, however, for low-carb dieters who opted for plant-based proteins over meat and dairy.)

“Whether you’re in the paleo camp or the keto camp or the vegan camp, everyone agrees that we want to have a nutrient-rich diet,” Axe says: “Lots of vegetables, herbs, spices, and plant-based sources of fat and protein, too.”

“If you’re not doing that, you’re promoting disease in the body—it’s that simple,” Axe says. (And yes, that’s true even if you still lose weight in the beginning.) “If you’re just going to eat butter and bacon,” he adds, “I’d rather you not do the keto diet at all.”

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Everything You Need to Know About the Keto Flu

The high-fat, low-carb ketogenic diet is *crazy* popular right now. It makes sense. Who wouldn’t want to try a diet that allows you to eat pretty much ~all the avocados~ and still potentially lose weight?! (To be fair, portion control still matters…that’s one of the many things people get wrong about the keto diet.) Still, the keto diet works really well for a lot of people with various health goals, from weight loss to athletic performance to getting type 2 diabetes under control.

But if you’ve tried keto yourself or know someone who has, you may be familiar with a phenomenon called the “keto flu.” Though many people who commit to keto end up feeling great eating this way after the kinks have worked out, the first couple of weeks can be, well, tough. Here’s why.

Keto Flu Symptoms

Sometime during the first couple of weeks on keto, many people report feeling, erm, not so great. “The most common symptoms are feeling tired, lethargic, achy, having a mild headache, cloudy, slow thinking, as well as possible lightheadedness and some hunger,” says Craig Primack, M.D., an obesity medicine physician who uses keto with some of his patients.

Cramping, muscle tightness, and moodiness are also possible, says registered dietitian Sylvia North. “In layman’s terms, you might just feel a little ‘off,’ as if you’re about to come down with the flu,” she adds. For most people, this lasts for anywhere from 12 hours to a week, but it really depends on the individual.

Why “Keto Flu” Happens

Here’s the bad news about the keto flu: There’s no hard data on exactly what causes it. Experts do have an idea of why it happens, though. “Most experts think the sensations are from adapting to a different fuel source,” explains registered dietitian Danielle Aberman. Normally, your body uses glucose derived from carbs for energy. When you’re in ketosis, your body begins using fat for energy, as well.

“The body is switching from being a carb-burning machine to a fat-burning machine,” says Aberman. “This is a significant metabolic shift that the average healthy person can do, but sometimes it can feel unpleasant.”

Most experts think hydration and electrolyte changes also contribute to keto flu, according to Aberman. “During ketosis, the kidneys get internal signals to make more urine. The increased urination causes increased loss of sodium, potassium, and magnesium in addition to the loss of fluid.” This is also what causes the initial drop in scale weight during the first week or so on the keto diet. As your body loses electrolytes and hydration, you start to feel less than amazing. (Related: How to Stay Hydrated When Training for an Endurance Race)

The good news? It’s totally temporary. “The symptoms of keto flu go away with time as your hormones and metabolism change to become more efficient at using fat for fuel,” says North. “This is sometimes called being ‘fat-adapted’ or ‘keto-adapted.'” Of course, how long it takes for this to happen varies from person to person.

Can You Prevent the Keto Flu?

It’s not known whether you can prevent the keto flu, but there are things you can do to try to optimize your experience with the keto diet from the beginning, says Aberman. First and foremost, staying hydrated is key.

Next, preemptively adding a little salt to your food may help. “Since the ketogenic diet is mainly composed of healthy, whole foods, the sodium content is often far less than the typical Western diet,” she says. “Salting your food is probably needed to give your body what it usually gets.” It’s also a good idea to choose foods that are higher in nutrients you lose when you start producing more urine (potassium and magnesium, for example) like avocado, spinach, and almonds.

It’s also important to note that not everyone will experience keto flu. “It does not happen to everyone, and the more times that you are in ketosis, the less likely it is to happen,” says Dr. Primack. In other words, keto flu isn’t inevitable, and if you’ve already tried the keto diet before, you may avoid feeling transitional symptoms altogether. This may be the case for people who practice carb cycling. (Related: How to Safely and Effectively Come Off the Keto Diet)

What to Do If You Have the Keto Flu

If you are dealing with keto flu, know that it won’t last forever, but here’s how to deal with the symptoms in the meantime.

  • Hydrate with liquids high in electrolytes. In addition to drinking more water, try some electrolyte-boosted liquids. “Some people find relief by sipping broth or dill pickle juice,” says Aberman.​
  • Take OTC meds if needed. “Some people with headaches find relief from the usual over-the-counter remedies like ibuprofen or aspirin,” says Aberman.​
  • Take it easy. A few days off from intense exercise is probably a good idea, experts say. Plus, it will take a bit before you’re back at peak performance. “It can be from four to eight weeks before you regain your top energy or performance power when exercising,” says North. (Heads up: Here are eight things you need to know about exercising on the keto diet.)​
  • Check in with your doctor or dietitian. While some period of adjustment is normal, it’s a good idea to consult a health care practitioner if things don’t seem to be improving. “If the initial ‘flu-like’ symptoms carry on for longer than a week, then it’s advised to seek professional advice,” says North.

Lastly, it’s worth noting that just like any eating style, the keto diet isn’t for everyone. “There is a subgroup of people that never seem to feel good on a ketogenic diet,” says Dr. Primack. On the other hand, “there are some patients that feel more energetic, clear, happy, and content after they transition to ketosis.” So, above all, it’s important to listen to your body and make adjustments accordingly.

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