Do Carbs Make You Fat?

You can eat carbs. Anyone can. And they are not the cause of weight gain.

Few things strike as much fear and create as much confusion as carbohydrates.

Are carbs bad? Are carbs unhealthy? Do carbs make you fat?

If you look back at the history of dieting, this is nothing new. In the 80s and 90s, you could replace “carbs” with “fat” and you’d be having the same conversation.

But, as time goes on and research improves we should have a better sense of what drives weight gain and weight loss. Unfortunately, carbs missed the science train and been stuck on the pseudoscience rollercoaster.

For years, I’ve heard some variation of, “I know that if I eat fewer calories I’ll lose weight. But, if I eat a couple of slices of bread or some rice, I’ll get fat.”

Fortunately, this isn’t true. You can eat carbs. Anyone can. And they are not the cause of weight gain. However, there are a few details that will help you figure out how many carbs you can eat and the types of carbs that are likely to be best for your body.

Why Do People Think Carbs Are Bad?

The easy answer is that most of the delicious foods that we can easily associate with weight gain also happen to be carbohydrates. Think candies, cookies, donuts, and any other deliciousness you can find at a bakery. All sugary sodas (and sugar, for that matter) fall into the carbohydrate category.


There are certain limits on how many (and how much) of those foods you can eat. They are not 100 percent off-limits (here are some guidelines for how much sugar you can have, and it’s not zero), but the more you eat those foods, the more you’re likely to pack on pounds.

But, carbohydrates also include fruits and vegetables, oats and grains, quinoa, and lentils. The Mediterranean Diet, which has a good amount of research supporting its ability to help maintain a healthy weight and reduce the likelihood of heart disease and other cardiovascular diseases, is a high-carb diet that features all of those healthy carb options.

Even rice — yes, white rice too — is a staple of the Japanese diet, which is linked to longer life and lower weight.

white rice

Some of the confusion is linked to the carbohydrate-insulin model of obesity. In a nutshell, this theory states that obesity is caused by carbohydrates, not calories. The idea is that carbohydrates increase insulin, which reduces the way our body is typically fueled (by glucose and free fatty acids). Instead, the insulin drives fat into our fat cells, we gain weight, become hungrier for more carbs (and insulin), and this becomes a hamster-wheel of weight gain.

There’s just one problem: whenever the model is tested, the claims don’t hold up and research does not suggest that carbs make us fat.

Just as importantly, if carbs were the driver of weight gain, then other macronutrients (like fat), arguably wouldn’t make us gain weight.

But, that’s also not the case. Two different studies have compared what happens when you eat too many carbs or fat. (You can find the research here and here.) What happened? Overeating fat resulted in the same outcome as overeating carbs, and sometimes overeating fat led to more fat gain than overeating carbs.

Now, this doesn’t prove that eating carbs don’t make you fat. However, it’s evidence that suggests you can gain weight regardless of insulin levels.

In other words, the goal isn’t to avoid carbs completely, but, instead, find the sweet spot for your body so you can enjoy foods, stress less, and be in control of your weight.

Are Higher-Carb Diets Healthy?

A healthy diet can (and arguably should) include carbs. After all, carbs help fuel many important processes in your body. This includes:

  1. Powering your heart and brain.
  2. Fueling anaerobic activity (think weight lifting) via glycolysis (the breakdown of carbohydrates).
  3. Helping with recovery by restocking glycogen (carb stores) that has been depleted through hard training.
  4. Supporting an anabolic (muscle-building) environment after training.

Safe to say carbs are not bad, regardless of your activity level. But, eating in a way that supports your activity level is important so that excess carbs don’t become unwanted weight gain.

Some people will thrive on more carbs, while others require less. The easy way to determine how many carbs you need (and how high you can go with your carb intake) is based on your activity levels (more on this soon).

That said, you can be very healthy on a higher-carb diet, and, at the very least, you should feel comfortable having some carbs in your diet without fear that it will lead to weight gain.

Need proof? The best example is a meta-analysis that compared carbohydrate intake ranging anywhere from 4 (super low carbs) to 45 percent (pretty high) of total calories, and fat content at 30 percent or lower in low-fat diets.

Here’s what the researchers found:

  1. Low-fat diets were slightly more effective at lowering total cholesterol and LDL.
  2. Low-carb diets were more effective at increasing HDL and decreasing triglycerides
  3. Neither diet was more effective than the other at reducing body weight, waist girth, blood pressure, glucose, and insulin levels.

This overall lack of differential effects led the authors to conclude that both low-carb and low-fat diets are viable options for reducing weight and improving metabolic risk factors. Read that one again.

And it’s not like this was a small study. It included 23 trials from multiple countries and totaled 2,788 participants.

What’s more, the cuisines of some of the healthiest populations in the world consist of diets that are heavy on carbs. The best examples are “The Blue Zones,” which are known as “longevity hotspots that have the longest life expectancies and the lowest rates of chronic and degenerative diseases.”

The main energy sources for all of these Blue Zones are carbohydrates. Need more evidence? The Top-10 countries in the world with the lowest obesity rates all consume a carb-dominant diet. 

OK, So What Are Healthy Carbs?

The easy answer is fruits and vegetables. The more complicated answer is that any type of carb can fit into your diet if you know how many carbs (and what types) you need, based on your activity levels.

fruits and vegetables

People who exercise regularly have very different dietary needs than sedentary populations.

If you are relatively sedentary or most of your exercise consists of low-intensity activities (such as walking), then you won’t burn through as many carbohydrates. In other words, if you don’t exercise often or at a higher intensity, 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.

Could you go the super low carb route? Of course, that’s also an option. But, for most people, it’s unsustainable and it does not offer any type of superior fat burning.

So, if it’s a good system for the way you like to eat, then you can cut carbs very low. If not, you just need to lower how many carbs you eat, not eliminate them completely.

How Many Carbs Should You Eat?

If you’re more inactive, an effective low-carb, non-ketogenic diet can be accomplished with roughly 100 to 125 grams of carbs a day from non-starchy vegetables, legumes (like beans), whole fruit, as well as a little bit of starch (such as oats, rice, or even pasta or bread). Preferably, the starch will only make up about 30 percent of your carb intake.

But, here’s the key point: 100 to 125 grams of carbohydrates is hardly a “no carb” diet, but it’s still low-carb.

High carbohydrate intakes, on the other hand, are more appropriate for gym rats and athletes that engage in intense muscle tearing, glycogen (carbohydrate)-depleting training sessions.

When you exercise, your body undergoes cyclical depletion (through training) and repletion (through carb intake) of muscle glycogen stores. As a point of reference, your muscles can store about 300 to 600 grams of carbohydrates.

The more you weigh (or the more you want to weigh), the higher you can go on the carb scale. And the more you train intensely, the more carbs you can eat and store as part of your recovery and growth.

While it’s true that lower-carb diets provide many health benefits and can help with weight loss, don’t confuse “low carb” with no carbs. Dropping all carbs is unnecessary, and — in many cases — that extra behavior leads to extreme struggles that result in binges and weight gain.

Instead, enjoy your carbs. Eat them based on your activity level and your personal experiences and sensitivities with different types of foods. If you’ve struggled with dieting, accepting that carbs are good and won’t make you fat is one of the most liberating decisions 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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