- For the Last Time: Carbs Don’t Make You Fat
- What are carbohydrates?
- ‘Good’ vs. ‘bad’ carbs? Not a thing
- The carbohydrate-insulin hypothesis of obesity
- When theory becomes dogma
- First rule of nutrition science? Don’t talk about your own dietary choices
- Do Carbs Make You Fat?
- Step 1: Do You Need Starchy Carbs?
- Step 2: Why Should You Eat Starchy Carbs?
- Step #3: Choose the Right Starchy Carb Source
- The White Rice Myth
- How To Eat Carbs and Stay Lean
- Eat The Way You Want (Carbs included)
- Cutting Carbs Does Not Increase Metabolism or Fat Loss
- Other Trials Show No Advantage From Cutting Carbs
- Do Carbs Make You Gain Weight?
- Indigenous And Pre-Industrialised Populations Thrived On Carbs
- Those Who Live Longest Eat A Lot of Carbs
- But A Low Carb Diet Works For Me?
- No, Carbs Don’t Make You Fat
- This Nutrition Coach Wants You to Know That Eating Carbs at Night Won’t Make You Gain Weight
- Does eating fat make you fat?
For the Last Time: Carbs Don’t Make You Fat
The definition of insanity is doing the same thing over and over again and expecting a different result.
First the Atkins diet claimed to be the solution to weight loss and health. It wasn’t. Now its younger cousin, the keto diet, is implying that you just weren’t restricting carbohydrates quite enough for it to work properly.
Can we stop demonizing carbohydrates already?
What are carbohydrates?
In a now infamous scene from her documentary “Homecoming,” a dejected Beyoncé reports, “In order for me to meet my goals, I’m limiting myself to no bread, no carbs, no sugar…”
…while eating an apple. Which contains carbs. If you’re going to remove something from your diet, you should probably know what it is first.
Carbohydrates are one of the three main building blocks, also known as macronutrients, that make up all food, alongside protein and fat. These macronutrients are essential for the body to function.
Carbs can be further split up into three groups:
- Sugars are simple short-chain compounds (monosaccharides and disaccharides) found in fruit like apples and the ubiquitously demonized white sugar. They taste sweet and tend to be highly palatable.
- Starch is a longer chain of sugar compounds (polysaccharides). This type includes things such as bread, pasta, grains, and potatoes.
- Dietary fiber is the odd one out. It’s also a polysaccharide, but the gut can’t digest it.
Remember, almost all foods that people call “carbohydrates” actually contain a combination of all three types of carbs along with protein and fat. Apart from table sugar, it’s rare to find something that’s purely a carb. That’s just not how food tends to work.
‘Good’ vs. ‘bad’ carbs? Not a thing
I’m not going to talk about this for very long, because there are hundreds of articles on the internet giving you lists of carbohydrates that you “should” and “shouldn’t” eat, pitting them off against each other like some sort of gladiatorial fight to the death.
I’m not going to do that.
Of course certain foods have more nutrients than others, and yes, the fibrous carbs are going to have the best overall impact on our health.
Can you do me a favor, though? Seeing as food doesn’t have a moral value, can we stop using the words “good” and “bad” when it comes to what we eat? It’s not helpful, and I’d argue it’s actually harmful to our relationship with food.
It’s possible to recognize the hierarchy of benefit that certain foods have without demonizing others to the extent of exclusion and restriction.
Now let’s get on to the main reason why I felt the need to write this article: Why do people believe that carbs make us fat?
The carbohydrate-insulin hypothesis of obesity
Hypotheses in science are made to be tested. The problem with this particular one is that it’s been falsified (proven incorrect) on multiple occasions, yet those who hold carbohydrates responsible for obesity have all built massive careers off it and would have much to lose by recognizing that fact. Money has a habit of ruining objective science.
When we eat carbohydrates, those polysaccharides and disaccharides have to be broken down by enzymes in our gut before our small intestine can absorb the resulting monosaccharides. After absorption, the subsequent rise in our blood sugar stimulates the release of insulin, which enables the cells to take up glucose and use it as an energy source.
Insulin also has the job of signaling the liver to store excess glucose as glycogen. The liver can only store a certain amount of glycogen at one time, so anything extra then gets converted to fat for longer-term storage, also under the control of insulin.
People usually freak out about that last bit, but relax: Fat storage is both normal and essential for proper functioning of the human body. Fat storage, fat breakdown… the whole thing is in a constant state of flux.
Glucose is the most important fuel source for the body. Due to the fact that we don’t eat every minute of the day, there are times when our blood sugar levels need increasing; that’s when the previously stored glycogen gets broken down back into glucose.
Fat can also be broken down to help, with fatty acids then being converted into glucose through a process called gluconeogenesis. As glucose is our brains preferential source of energy, there are many mechanisms in place to keep our blood glucose levels stable. It’s a no-brainer (pun intended).
When these mechanisms aren’t functioning properly (in conditions such as diabetes), our health tends to suffer.
Since insulin upregulates fat storage and downregulates fat metabolism, it seemed reasonable to test the hypothesis that if we kept insulin stimulation at a minimum by restricting carbs, it might be easier to mobilize and use fat for energy.
Yet before it could be tested fully, people started preemptively claiming that low-carb diets (originally Atkins, more recently keto) were best for weight loss, and insulin stimulation was the reason for weight gain and obesity.
When theory becomes dogma
There are lots of nuances to this hypothesis, with many different elements having subsequently been proven incorrect, but there isn’t time to go into them all in this article.
So, let’s focus on the main one.
In science, a hypothesis becomes proven incorrect when an integral part of it is shown to be wrong. The theory that insulin stimulation directly causes weight gain can be tested by comparing rates of weight loss between people on a high-carb diet versus a low-carb diet (when calories and protein are kept the same).
If the theory is correct, those on the low-carb diet should lose more weight due to a lower stimulation of insulin.
The best way to test this out is through utilizing metabolic ward studies. These create a highly controlled environment with participants living and sleeping at the lab for the duration of the study. All movement and food intake is measured and recorded. (I can’t image it’s particularly pleasant for those involved!)
Fortunately for us, this hypothesis has been appropriately tested time and time again over the last three decades. This 2017 systematic review and meta-analysis by Hall and Guo looked at 32 different metabolic ward studies. The results were outstandingly clear: When calories and protein are controlled, there’s no energy expenditure or weight loss benefit from eating a low-carb diet over a high-carb diet.
In the end, weight manipulation comes down to calorie control, not insulin control. Whether or not we should be doing so is something I’ve touched on in a previous article.
First rule of nutrition science? Don’t talk about your own dietary choices
We have a problem in the scientific community, and that problem is identity.
Low-carb has become part of one’s identity, with the rise of “low-carb doctors” and “low-carb dietitians.” Despite all the available evidence falsifying the carbohydrate-insulin hypothesis of obesity, many are unwilling to let go of their dogma and genuinely explore the evidence and their identity.
So, in the end, I think it’s down to the rest of us who haven’t registered our identity yet to a certain way of eating to keep holding up the truth in the face of dogma. It will take some time, but if we don’t champion critical thinking and good science, what are we left with?
I wanted this article to be a stand-alone, specifically looking at the carbohydrate-insulin hypothesis of obesity. I know a number of you will have other reasons as to why you’ve been told to eat a low-carb diet, and I’ll look at sugar, diabetes, “low-carb for health,” and all the nuance that brings another time. Hold tight.
Dr. Joshua Wolrich, BSc (Hons), MBBS, MRCS, is a full-time NHS surgeon in the United Kingdom with a passion for helping people improve their relationship with food. One of the few men in the industry addressing weight stigma and diet culture, you can find him on Instagram regularly combating spurious nutrition information and fad diets while reminding us that there’s so much more to health than our weight. Keep an eye out for his upcoming podcast, “Cut Through Nutrition,” for an in-depth look at the appropriate use of nutrition in medicine.
Few things strike as much fear and create as much confusion as carbohydrates. Are carbs bad? Are carbs unhealthy? Do carbs make you fat? In the last decade, we’ve easily transformed from a society that feared fat, to one that is now terrified of carbs. Just the other day I was in the bookstore pretending to be a big deal author (yes, my new book is now available for purchase—you can pick it up here), and a woman started talking to me about diet. She said, she knew all the tricks.
“I know that if I eat fewer calories I’ll lose weight. But here’s the thing: If I eat a couple of slices of bread or some rice, I know I’ll get fat. Isn’t that crazy.”
Well, yes. It is crazy. Mainly because it’s not accurate. And yet, that’s what most people believe.
In order to help restore some balance to the carb question, I reached out to Nate Miyaki. Nate’s been working on the nutrition side of the fitness world for more than 10 years, and has been an invaluable resource for many of the articles I’ve written.
If you’re inactive, you only need to worry about providing carbs to fuel your brain and central nervous system. If you’re active, it’s a different story.
He also happens to be well versed in both the science of carbs, as well as real life application. That is, when you design programs and diets, do carbs really make people fat?
To answer that question, I had Nate discuss the truth about one of my favorite carb sources—white rice. Here’s what he had to say. -AB
Do Carbs Make You Fat?
Who would have thought my tiny little morsel of goodness could cause so much controversy.
I’m talking about my favorite food–rice, rice, baby.
Whether or not rice should be included in a health enhancing, fat slashing, muscle building diet is a highly debated topic in our industry. To some (such as certain followers of the Paleo movement), rice is a demon food that should be avoided like the plague.
Yet in some cultures that exhibit immaculate biomarkers of health and low obesity rates, it has been a dietary staple for centuries. What gives?
I ate 5 cups of rice last night for dinner. I’m also close to 5% body fat, so I can tell you what side of the fence I’m on. I think sugar, high fructose corn syrup, trans fats, and high omega-6 vegetable oils do more to cause insulin resistance, diabetes, and obesity than my pal white rice.
But most of us don’t want to give up our beloved junk foods, so we have to blame something. White rice is as easy of a target as any. So in order to help you determine whether carbs–or rice–should be a part of your diet, I’ve developed a simple three-step system to help you figure out your nutrition needs.
Step 1: Do You Need Starchy Carbs?
A core problem in the fitness industry is trying to slot everyone into one universal diet system. It just doesn’t work that way my friends.
Intense exercise changes the way your body processes nutrients, and your internal physiological, metabolic, and hormonal environment for 24 to 48 hours. That means athletes and regular exercisers have very different dietary needs than sedentary populations.
Beyond any scientific debate, that’s really just pure common sense. So the first step in this carb selection story is to assess how many carbohydrates you really need, and for what reasons.
A sedentary person who does not exercise will not burn through muscle glycogen reserves (think of this as energy or carbohydrates), which are really only used for high intensity muscular contractions (hence the name).
So inactive individuals do not need to worry about replenishing these stores with the ADA-recommended carbohydrate levels. In other words, if you don’t exercise your carbohydrate needs are much less.
If you’re inactive, you really only need to worry about providing adequate carbohydrates to fuel your brain and central nervous system at rest, which is primarily regulated by your liver glycogen stores (80-110g).
Could you go the super low carb route? Of course, that’s also an option. But if you do, be aware that it might be associated with ketogenic (low carb)-induced brain fog, grumpiness, depression, insomnia, and low testosterone.
So How Many Carbs Should I Eat?
An effective low-carb, but non-ketogenic diet, can be accomplished with roughly 100 to 125 grams of carbs a day from unlimited, non-starchy vegetables and a few pieces of whole fruit. No rice or starch is necessary.
But here’s the key point: 100 to 125 grams of carbohydrates does not mean eating no carbohydrates. It just means that your demands are less, and your carb sources are best reserved for fruits and veggies. Can you eat other carb sources and stay within that carb range and still be healthy? Of course. But you might lose out on some other nutritional benefits.
High carbohydrate intakes, on the other hand, are more appropriate for gym rats and athletes that engage in intense muscle tearing, glycogen depleting training sessions.
When you exercise, your body undergoes the cyclical depletion (through training) and repletion (through targeted starch intake) of muscle glycogen stores. That can take a lot more than 100 grams because beyond what supports the liver, your muscles can store about 300 to 600 grams of carbohydrates.
If you drive your car around and empty the gas tank, you need to fill it back up to keep it functioning properly. So in those cases, on the days that you train, depending on your bodyweight and goals you might need several hundred grams of carbohydrates to help your body recover and grow.
Step 2: Why Should You Eat Starchy Carbs?
By now, I hope you understand that the only reason you need starch is for the single, sole purpose of obtaining the high-powered glucose molecules within that food, which in turn can be used to:
1. Fuel anaerobic activity (think weight lifting) via glycolysis (the breakdown of carbohydrates).
2. Restock glycogen (carb stores) that has been depleted through hard training.
3. Trigger an anabolic (muscle-building) environment that offsets, and hopefully exceeds, the initial catabolic stress brought on by intense training.
The moral of the story is that for people who exercise, it’s the glucose chains in starchy carbs that really matter, not all of the additional compounds that sometimes come along with them.
If you are eating starchy carbs for any other reason than to obtain those glucose chains, I believe you are eating them for the wrong reasons. That’s a lot of fancy science talk, so here’s what you really need to know. These are bad reasons to choose certain carb sources:
- I choose “x” carb because it is high in protein
Grain proteins are of inferior quality and bioavailability than animal proteins. You should be getting the majority of your protein needs from high quality animal sources. Any protein in grain foods is incidental, not necessary. The obvious exception: If you follow a vegetarian or vegan diet, this rule changes.
- I choose “y” carb because it is high in fiber
Fiber is invaluable for overall health, but I believe you are better off getting the bulk of your fiber, so to speak, from natural plant sources — like fruits and veggies — rather than man-made cardboard — like fiber twigs and sawdust.
- I choose “z” carb because it is low glycemic
Chronic elevations in insulin can definitely be problematic, and can lead to a host of diseases including diabetes and Man-Boob-itis. But short-term (acute) elevations under certain metabolic conditions can be highly beneficial to the athlete. Insulin transports amino acids and glucose into the muscle cell to initiate the recovery process from training.
You should indeed choose low glycemic fruits and vegetables the majority of the time (and if sedentary, all of the time). But a higher glycemic food – oh I don’t know, like white rice – can work magic in a targeted, post-workout recovery period.
Step #3: Choose the Right Starchy Carb Source
Here’s the real reason why carbs get such a bad reputation: Up to 50 percent of the carbohydrate intake in the typical American diet is in the form of high fructose corn syrup and sugar. This often serves as the “control” group in most studies.
So when people say carbs are bad, they’re usually just talking about eating lots of sugar. But that’s not really fair to every other food that also is labeled a carbohydrate.
When compared to a typical American diet, the low carb diet is going to look like the undisputed world champ. However, when compared to a good carb-based diet that is low in sugar, refined foods, and gluten (like the “Japanese Diet”), the results are very different.
In Japan, diabetes and obesity rates were never greater than 3 percent of the population pre-1991. If carbs in general were the enemy, with their high starch intake via rice and sweet potatoes, the Japanese would be the fattest, most diabetic and unhealthy population on the planet. However, this was not the case.
Condemning all carbs as evil and cutting them across the board, regardless of the type or individual metabolic situation, is an uniformed approach.
Finding the Right Carb Source For You
Athletes and people that exercise may benefit from the inclusion of some carbs into their diets, but it is critical they make the right choices in terms of carbohydrate type. You should choose starches that provide anaerobic fuel without all of the damaging toxic compounds.
The following foods can be consumed in your diet, but you might want to limit their consumption for various reasons:
- High fructose corn syrup and refined sugar (one molecule of glucose plus one molecule of fructose) can lead to insulin resistance, diabetes, and obesity.
- Gluten-based starches (wheat, rye, barley) can be problematic because gluten is a protein that is an allergen or food sensitivity for many and can cause bloating, water retention, stubborn fat, and lethargy. (Remember, this is only if you have an allergy or sensitivity to gluten; it is not universally evil or problematic.)
- Beans and legumes are lectins that can cause GI distress, leaky gut syndrome, and can inhibit protein digestion and amino acid absorption.
- Most cereal grains contain the “anti-nutrient” phytic acid. This compound can also cause GI distress and inhibit mineral absorption.
In terms of carb sources that are universally healthy for people, we’re not left with much. That’s why the Japanese Village-style Diet works as a simple dietary template for active individuals: animal proteins, non-starchy vegetables, whole fruit, and starchy carbohydrates coming predominantly from root vegetables (yams, sweet potatoes, potatoes) and white rice.
The White Rice Myth
Isn’t brown rice so much better than white? Not necessarily. Remember, it’s better to receive your fiber from plant foods and not 87 servings of whole grains. Brown rice is like most other cereal grains.
The “anti-nutrient” or phytic acid that is problematic for digestion and nutrient absorption is located in the bran of the grain. This is removed in the milling process that essentially changes brown rice to white rice. It is one of the few exceptions where I believe food refining is actually beneficial. When you remove the bran, what you’re left with is an easily digested, “safe starch” food without any toxic compounds.
How To Eat Carbs and Stay Lean
Carbs are not evil.
While it’s true that lower carb diets provide many health benefits and can help with weight loss, low carb does not mean no carbs. When you’re training and exercising, your needs for carbohydrates increases. And if you’re trying to gain muscle, carbs are an essential part of the equation.
What’s more, for many people, white rice is, in fact, one of the best carbohydrate sources because it isn’t associated with stomach distress, allergies, bloating, and it’s not loaded with sugars that are linked to diabetes or obesity.
So enjoy your carbs. Eat them based on your activity level, and your personal experiences and sensitivities with different types of foods. But no matter what, don’t just assume a food is bad (or makes you fat) because it’s a carbohydrate. It’s one of the bigger nutritional mistakes you can make.
Eat The Way You Want (Carbs included)
If you want help building muscle, losing fat, or for me to personally design a customized exercise and diet plan, join me in my coaching program. You can apply here.
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Fix Your Diet: Understanding Proteins, Carbs and Fats
Cutting carbs is the most important change for weight loss.
At least, that’s the idea sold by Gary Taubes, Dr. David Ludwig and other low carb enthusiasts.
They believe carbohydrate drives obesity because it raises the hormone insulin. Insulin is said to block the release of fat and also drive additional fat storage.
However, nutrition research continually shows that carbs alone DON’T make you fat. The latest clinical trial is no exception.
You might’ve already seen my stance on this. But let’s put our personal food ideologies aside for a moment to honestly consider the weight of evidence available.
Cutting Carbs Does Not Increase Metabolism or Fat Loss
Journalist, Gary Taubes
If raised insulin drives weight gain, then conversely, reduced insulin (from cutting carbs) should be therapeutic.
In other words, we’d expect an extremely low carb diet to cause more fat loss than a typical Western diet.
The latest trial to compare these two eating patterns – ironically funded by Taubes’ own NuSI organisation – indicates this is not true.
This was a tightly-controlled, metabolic ward trial, which means no cheating on the diet.
For 4 consecutive weeks, 16 overweight or obese men were fed a standard American diet, quite high in carbs (50% Carbohydrate, 15 % Protein, 35% Fat).
According to the sample menu published, it included loads of refined carbs including lemonade, granola bars, pretzel sticks and sandwich bread.
Participants were then immediately switched to a very low carbohydrate, ketogenic diet (5% Carbohydrate, 15% Protein, 80% Fat) for another 4 weeks (1).
Both the high carb diet and the ketogenic diet were equal in calories and protein, and they had no access to any outside foods for the entire 8 week period. Participants also rode an exercise bike for 30 minutes daily.
Example of daily menu. Source: Vox
Changes in energy expenditure, body composition and relevant blood markers were recorded each day using the gold-standard methods where possible.
After the first 4 weeks on the high carb diet, participants lost 1.1 lbs (0.5 kgs) of body fat on average.
Switching to the low carb diet for the remaining 4 weeks led to a dip in insulin levels by almost half. However, once again participants lost just 1.1 lbs of body fat.
Source: Stephan Guyenet
So there was no difference between eating patterns on fat loss despite the difference in insulin, effectively disproving the carbohydrate-insulin hypothesis.
Switching to the low carb diet did cause an initial sharp decrease in total weight loss, but this was due to the drop in water weight that accompanies carb restriction (2).
Source: Smart Training & Flexible Dieting
To be fair, the low carb diet did increase metabolic rate by 57 calories per day on average. This outcome was actually the main aim of the study.
However, this number started much stronger before plummeting down to about 40 calories per day, which is clinically insignificant. In fact, the metabolic advantage all but disappears after several weeks.
Some will say that 40 calories x 365 days per year = 14,600 calories per year. This equals 4.1 lbs (2 kgs) of weight loss in a year, assuming a 3,500 calorie deficit equals 1 lb of fat.
But it doesn’t actually work like that. A daily deficit of 40 calories is likely to equal only 4 lbs of weight loss after 2-3 years, if you don’t cheat.
Is that worth cutting your diet to strictly 5% carbs?
Summary: A well-designed clinical trial, funded by low carb advocates, found a low carb ketogenic diet was not beneficial for fat loss or metabolic rate. The high carb diet was just as effective – if not better – for body fat loss, despite the higher insulin levels.
Other Trials Show No Advantage From Cutting Carbs
This was not the first well-controlled clinical trial to show cutting carbs has no advantage for fat loss.
In fact, it was shown over a decade ago.
In a 6-week trial of 20 subjects randomly assigned to follow either a ketogenic diet (5% carbs) or a moderate carb diet (40% carbs), there was no difference in average weight loss, fat loss or insulin changes. All food and beverages were provided to participants (3).
If anything, strictly cutting carbs leads to less fat loss as time goes on. Subjects also reported the ketogenic diet was worse for feelings of energy and overall mood.
There was also a smaller and slightly different version of the above NuSI study, also run by Dr. Kevin Hall.
His team found a reduced carb diet (29% carbs) resulted in less fat loss than a reduced fat diet (7.7% fat). At the time, their computer model even predicted the trend seen in the latest study (4):
Change in fat mass of reduced fat vs reduced carb. Source: Examine.com
Although the reduced carb diet (29% carbs) was not quite “low carb”, it still lowered insulin levels considerably. Despite this change there was no fat loss advantage.
Summary: Several other well-controlled trials looking at the fat loss effects of reduced carb and very low carb ketogenic diets indicate they are not beneficial for long-term fat loss.
Do Carbs Make You Gain Weight?
It’s evident that restricting carbs is unnecessary to lose weight… But what about gaining weight?
Is overeating carbs worse than overeating fat, as per carbohydrate-insulin hypothesis?
This has also been well-studied, and clinical trials show this is not the case, per unit calorie.
In a study of 16 men (9 lean and 7 obese), subjects were fed a strict diet providing 150% of caloric requirements (designed for weight gain). The additional 50% of calories came from either carbohydrate or fat for 14 days at a time. Subjects completed both diets in a crossover design.
Researchers found that both carbohydrate and fat overfeeding caused almost identical increases in body weight, fat mass, and lean mass (5).
These increases did not differ between the lean and obese subjects either.
Source: Stephan Guyenet
Another similar overfeeding study of 20 lean men also found no differences in the increase of total weight or fat mass gained after 21 days (6).
It appears when calories are matched, there’s no difference in fat gain between overeating carbs or fat.
What About When We Don’t Overeat?
Do carbs influence body fat in individuals who are not overeating calories?
In a series of tightly controlled clinical studies, 15 subjects were fed a diet that shifted greatly in the amount of carbs or fat it contained over a 13-week period. The calorie amount was for weight maintenance (no gain or loss), and was kept the same regardless of the carbohydrate-to fat ratio (7, 8).
This is how one subject’s weight tracked throughout the study. The first 38 days were high carb (75% carbs), the remaining were low carb (15% carbs).
The researchers concluded, “The carbohydrate-to fat ratio could vary widely with little or no alteration in the energy requirement for weight maintenance.”
Therefore, if you aren’t consuming excess calories, weight stays the same regardless of the amount of carbs you enjoy.
Summary: Clinical studies show that eating carbs instead of fat makes no difference to body fat, as long as total calories remains the same. This holds true whether we overeat calories or not.
Indigenous And Pre-Industrialised Populations Thrived On Carbs
Tarahumara Indians (source: Wikipedia)
Still not convinced that carbs are not uniquely fattening?
Even if we ignore the clinical studies (the most powerful evidence available), the carbohydrate-insulin theory doesn’t fit the historical and observational evidence.
Indigenous groups like the Tarahumara Indians, Kitavans and Massas all thrived on high carb diets for hundreds of years. Obesity was rare (if not non-existent) in all of these indigenous groups (9, 10, 11).
For example, Kitavans had virtually no overweight people – and very low insulin levels – despite a diet that was 70% carbs (12).
Kitavans (source: Staffanlindeberg.com)
The same was observed for pre-industrialized Asian populations up until the 20th century, living on staple foods like rice, noodles, potatoes and fruit (13, 14).
Even by the 1990’s, 50-60% of calories eaten in Japan and China still came from carbs. This was more than the US or UK, yet obesity rates were much lower (15).
If carbs themselves are fattening, these populations would not have had lean bodies and good health overall, regardless of how active they were.
Taubes’ counter argument is that obesity was not uncommon in many native populations from the 1950’s onward. However, by this time many developing nations and Indigenous groups – such as the Pima Indians – already had access to refined, affordable (often subsidised) Western food.
Summary: There are numerous historical examples of populations that remained slim and healthy eating high carb diets. This indicates carbs themselves are not fattening. Indigenous groups only became obese after the introduction of Western junk food.
Those Who Live Longest Eat A Lot of Carbs
There are still modern day humans thriving on high carb diets too.
In fact, many of them have the lowest rates of metabolic disease and obesity, and live longer than anyone else. The regions where they live – known as Blue Zones – give us valuable insights into the lifetime effects of certain eating patterns.
The Japanese island of Okinawa has the greatest proportion of centenarians (people over 100 years old) in the world.
Their diet has always been carb-dense; high in sweet potatoes, legumes and rice to a lesser extent. In fact, a massive 85% of an Okinawan’s caloric intake came from carbs prior to the 1950’s. Sweet potatoes alone accounted for 69% (16).
More than 65 years later and so many of them are still alive and well.
Source: Okinawa Centenarian Study
Those from the Greek Island of Icaria also live long and healthy lives, despite a diet high in bread, potatoes and legumes.
Almost 1 in 3 inhabitants lives to be 90 years old, which is 2.5 times the rate of Americans (17).
Source: The NY Times
Other Blue Zone regions share similar dietary traits to the Okinawans and Icarians, so it’s not just a freak coincidence.
Granted their active lifestyles is a factor to their longevity, but a high carbohydrate diet does not cause them to get fat or sick.
Summary: The world’s longest living populations have diets rich in carbohydrate foods.
But A Low Carb Diet Works For Me?
Studies show low carb diets can be an effective strategy for weight loss.
Especially if you previously struggled following a low fat diet.
But it’s not because carbs alone made you gain fat. Nor is it because cutting carbs alone made you lose fat.
A reduction in carbs automatically means an increase in protein and/or fat. It’s this entire nutrient ratio shift – coupled with an increase in whole (unrefined) foods – that’s responsible for the positive outcome.
Studies show a diet higher in protein keeps you feeling full and tends to decrease overall calorie intake, at least in the short term (18, 19, 20).
A diet lower in refined carbohydrate and fat – typically found together in junk food – also favours a reduction in calorie intake. This is because of how calorie-dense and highly palatable junk foods is.
Then there’s also the loss of water that accompanies carb reduction. Alongside fat loss, this makes the bathroom scales shift favourably, and quickly (2).
The combination of these factors is why a low carb diet so often leads to weight loss. Replacing refined carbs with protein (and possibly fat) can help to consistently curb your appetite and reduce total caloric intake, without relying on willpower.
Summary: Many are successful on a low carb diet because it automatically higher in protein, which helps to curb appetite. They also typically eliminate all junk foods, which is where our excess calories come from.
No, Carbs Don’t Make You Fat
The science is in.
Carbs are no worse for your waistline than any other nutrient.
Studies show that when low carb and high carb diets are matched for calories, there is zero difference to body fat change. Regardless if your total caloric intake is excessive or not.
This makes sense considering all the past and present populations that thrive on high carb eating patterns.
That’s not to say carb-laden junk foods and soft drinks are off the hook. These products are low in nutrients and do not make you feel full or satisfied. They are undoubtedly the biggest contributors to excess calories, and therefore one of the main drivers of obesity and related health problems.
But it’s because of junk food as a whole – the total calories – and not just the carbs.
If you enjoy a low carb eating pattern and it’s improved your health then there’s no reason to stop. It may even be superior to low-fat for managing diabetes.
But there’s no need to cut carbs to extremes, such as a ketogenic diet.
And just know that cutting carbs is definitely not the only way to be healthy or lose weight…
So stop telling people it is.
One of the biggest misconceptions and fears for women is worrying that they can’t eat carbs and that by doing so, they will gain weight.
As we’ll explain though, total calories are what matters and that carbs are simply calories. So, as long as you reach your calories, you absolutely can and should include them in.
Whilst it does take some time to build your confidence up to eat more carbs, you typically get better results knowing that you can. This is because it just makes it easier as you can focus on what matters (your calories), you don’t have to eliminate so many foods and it’s probably true that at least some of your favorite foods contain carbs.
Here’s why carbs don’t make you gain weight.
Carbs Are Simply Calories
To lose weight, as you may have heard and it’s very true, you have to make what we call a calorie deficit. Each day your body burns what’s known as calories, which for most women will be between 1400 and 2000 each day. When you eat below that, your body taps into its energy stores and you lose weight.
So how do carbs fit into this?
Carbs simply contain calories:
- Fat: 1 gram = 9 Calories
- Protein: 1 gram = 4 Calories
- Carbs: 1 gram = 4 Calories
The total calories are what matters. Weight loss studies have consistently shown this to be true as well (study, study, study). As long as you know and reach your calories, carbs are fine.
This is the reason many fitness models and those lean like myself eat plenty of carbs yet don’t gain weight.
On the other hand, there are many that eat completely clean and low carb yet struggle a lot with their weight.
Now, it’s pretty common that you initially lose weight on a lower-carb diet. However, this is due to glycogen and water weight and is not true weight loss (this can also be the reason you can gain a little weight if you eat more carbs, but don’t stress, it’s not body fat).
One of our clients Shannon was initially stuck on a really low carb diet. Since then she increased her carbs (mostly from fruits) whilst still reaching her calories and didn’t gain weight.
And she’s also said that she feels like she’s able to eat a lot more for the same calories and crucially doesn’t have to stress that she gained weight by eating something with carbs in them.
You can eat carbs as long as you still reach your calories
Focus On Your Calories
To start getting toned, you want to focus on your calories first and foremost. You want to make sure to know your:
- Weight Loss Calories
- Maintain Weight Calories
Once you have these, focus on reaching them each day. This is what really matters, and you can include carbs into your diet providing you still reach your calories.
You don’t have to start with root vegetables, instead, as we typically recommend, you can start eating more fruits. Fruits are typically very low in calories (which is great for weight loss) but also are low GI as you build your confidence up.
But the above is the reason carbs are absolutely fine. So you can include more carbs in and you don’t have to pass up your favorite ice cream that has some carbs in it.
This Nutrition Coach Wants You to Know That Eating Carbs at Night Won’t Make You Gain Weight
A few days ago, Eng went out for a late-night dinner with a couple of her friends and ordered spaghetti. “Two of the other girls said they don’t eat carbs at night because they are afraid carbs would make them fat,” she recently shared on Instagram. (Related: Why You Should Give Up Restrictive Dieting Once and for All)
But the truth is, carbs won’t make you gain weight as long as you’re eating within your “energy budget,” Eng explained. “As in you are eating the same amount of energy that you burn,” she wrote. “As long as the calories you’re consuming at night are within your body’s required amounts, you will not gain weight!” (Related: How Many Carbs Should You Eat In a Day?)
Eng says that’s true for any macronutrients you choose to consume later in the evening. ” doesn’t matter if it’s either of your macros: carbs, fat, protein-your body simply won’t gain weight at night unless you’re eating above your macros!” Of course, that’s given that you’re already eating a balanced diet, properly counting your macros, and living an active lifestyle. It’s also worth noting that every body is different; research shows that individual factors like your metabolism, hormones, and insulin levels can all play a role in how your body processes and stores carbs. Plus, the types of carbs you consume late at night can have a negative impact on your weight long-term.
Overall, Eng’s point is that healthy carb consumption can actually be conducive to your lifestyle. She explained that she personally loves eating lean turkey for extra protein and incorporating carbs around her training sessions for improved energy and recovery.
Carbs have sadly gotten a bad rap for quite some time. In fact, this could explain why people continue to experiment with their carbohydrate consumption through methods like the trendy keto diet, which forgoes carbs almost completely, carb cycling, which allows those on low-carb diets to adjust their intake based on the timing of their tougher training days, and carb backloading, which involves eating most of your carbs later in the day. The list goes on.
But it’s important to remember that beyond bread, pasta, rice, and potatoes, carbs are also found in fruit, green vegetables, legumes, and even milk. These foods are full of other healthy nutrients, including B vitamins, vitamin C, potassium, calcium, and fiber, so if you limit carbs, you could be missing a lot of the good stuff that helps your body thrive.
As Eng says, as long as you’re being smart about your carb intake, and keeping an eye on both quantity and quality, when you’re consuming them shouldn’t really matter. (Looking for ways to fuel up on carbs? Check out our healthy woman’s guide to eating carbs-which doesn’t involve cutting them.)
Does eating fat make you fat?
Whether you gain or lose weight depends on your total caloric intake, rather than on your macronutrient ratios. That said, there are reasons why, in theory, eating fat is more likely to make you fat. We’ll review those reasons, then we’ll see if the evidence supports the weight-loss superiority of low-fat diets.
The case against dietary fat
Dietary fat is the macronutrient that can most easily increase your body fat: the two types of fat are essentially the same, so making the former into the latter is easy for your body. Dietary fat has a TEF of just 0–3% (of the three macronutrients, it requires the least energy to digest, relative to the energy it provides), and it gets stored with 90–95% efficiency (compared to 75–85% efficiency for carbs).
When you eat carbs, your body can, in order of priority, burn them for energy, store them as glycogen, burn them off as heat, or, as its very last choice, turn them into fat. So if you overeat with carbs as your main source of calories, the excess might not translate as fat gain.
When you eat protein, your body can, in order of priority, use it for protein synthesis and many other metabolic purposes, burn it for energy, or, rarely, turn it into glucose or fat. So, again, if you overeat with protein as your main source of calories, the excess might not translate as fat gain.
When you eat fat, however, your body has only two options: burn it for energy, if neither carbohydrate nor excess protein is available, or store it as body fat. If you overeat with fat as your main source of calories, even for just one day, the excess translates as fat gain.
Since your body will burn carbs and even excess protein before it burns fat, how much fat you eat won’t substantially affect how much carbs or protein you burn, but how much fat you burn will depend on how much carbs (and, to a lesser extent, protein) you eat. To put it another way, how much carbs and protein you eat will affect your total caloric intake, and if you consume more calories than you burn, then all the excess dietary fat gets stored.
Another problem with fat is its caloric density: 9 Calories per gram, versus 4 for protein and carbs. Just as their low caloric density makes high-fiber, high-water foods satiating, fat’s high caloric density makes it less satiating.
Of course, the satiating effect of a given food doesn’t depend only on its macronutrient content, and different foods affect different people differently. In other words, if you find certain high-fat foods satiating, it doesn’t mean you’re weird or the science is wrong; it just means that human trials cannot test every possible variable.
Dietary fat is more calorie-dense and, as a rule, less satiating than protein or carbs. Your body finds it easy to digest and store as body fat.
The lowdown on low-fat diets
Considering all we’ve said so far, you could be excused for thinking that, when the goal is weight loss, a low-fat diet is the way to go. Yet, in practice, the evidence is mixed. For each human trial that reports greater weight loss from low-fat, there seems to be one that reports greater weight loss from low-carb.
The best trial to date lasted 12 months: called DIETFITS, it found that a healthy low-carb diet and a healthy low-fat diet led to similar weight changes. Further, it noted that “neither genotype pattern nor baseline insulin secretion was associated with the dietary effects on weight loss”.
It is important to note that, like other studies, DIETFITS found the weight-loss difference between the low-carb group and the low-fat group to be very small compared to the weight-loss variations within a same group. In other words, interindividual differences seem to matter more than the diet being low-fat or low-carb.
In fact, when compiling the data, we realize that low-fat or low-carb may not even matter at all in the long run. Whereas a 2015 meta-analysis of diet trials reported modestly greater weight loss from low-carb diets, a meta-analysis of diet trials published the year before had found that, after a year, low-carb and low-fat diets balanced out:
Now, these studies all give us great information on the real-world effects of low-fat and low-carb diets, but they have their limitations: food intake was not controlled and diets were self-reported. Also, in some of them, there were differences in energy and protein intake between groups, making it impossible to isolate the fat and carb contributions to the findings.
Therefore, it is notable that a meta-analysis of 32 studies whose participants were fed by the researchers (thus ensuring that, within each study, each diet had different amounts of fat and carbs but the same amount of protein and calories) reported that low-fat diets resulted in greater energy expenditure (by an average of 26 Calories per day) and greater fat loss (by an average of 16 grams per day). The diets varied widely in carbs (1–83% of calories) and fat (4–84% of calories — so yes, ketogenic diets were included).
An extra 16 grams of fat loss per day amounts to about a pound of fat each month, so 12 pounds a year. But don’t declare victory for low-fat yet — these were highly controlled feeding studies, and real life isn’t highly controlled. In the real world, some people will lose more weight on a low-carb diet, due to factors such as limiting junk food choices and encouraging higher protein intake.
Low-fat and low-carb diets produce similar weight-loss results, at least in long-term clinical trials. Both types of diet work mostly because the trials’ participants reduce their intake of calories, not just of carbs or fat, and because eating less carbohydrate or fat usually results in eating more protein.
If you wish to lose fat, dieting comes first, exercise second. No supplement will replace either, but some supplements can make both more efficient. To learn which supplements are backed by the evidence and how to take them (when, in what dosages, and in what combinations), read our constantly updated Fat Loss Supplement Guide.