Carbohydrates tend to be a very misunderstood topic. Some people swear by them and others avoid them like the plague. There are many reasons why people do this. In this article, we will talk about some of the common misconceptions around carbs and what’s actually true. The topics that will be covered will include: if carbs make you fat, how carbohydrates and energy are related, if carbs make you sleepy, and carbohydrates and inflammation in the body.

 

Carbs and Body Fat

If you are someone who cuts their carbohydrate intake when they want to lose weight, you might be going about it the wrong way. Lowering your carb intake can help you lose fat, but it is not the actual reason you lose the weight. To understand why this is, we must understand one of the fundamental purposes of body fat.

Every day, our bodies need to produce a certain amount of energy in order to function (i.e. keep your heart beating, breathing, walking, etc.). This energy is measured in the form of calories, just as distance may be measured in the form of feet. Our bodies can produce energy from carbohydrates, fats, and protein. The fat stored in our body serves as an energy source when our body needs it, sort of like a gas tank.

Therefore, if in a day we eat less calories from food than our body needs to function, it will be forced to burn your stored fat. If on another day you eat more calories than your body needs to function, some of those excess calories will be stored as body fat to be used for energy later when your body needs it.

Eating less carbs may help you lose fat, but it is because you are taking in less energy overall. If you eat less carbs but eat more dietary fat, and your overall intake of energy for the day is the same, then you won’t see any difference in body composition.

To really test this, Sartorius et al. ran a review to evaluate how carbs and obesity are related [1]. The review included 22 different studies in which subjects were older than 18 and were at a healthy body weight, overweight, or obese. They looked at the diets of these individuals pertaining to carbohydrates as a percent of total energy intake and high carb versus high fat diets. They found that increase carbohydrate intake did not increase the rate of obesity. Further, this review added evidence to the idea that energy intake and output is the driver of body composition and weight and fat loss or gain.

The area where carbohydrates may become problematic is in how full they make you, particularly with sugary foods. Foods that have a lot or sugar tend to not be very filling for how many calories they have. For example, if you ate 300 calories of sugar cookies or 300 calories of chicken breast, you will likely feel much fuller after the chicken breast. This can make it very easy to overeat this type of food and therefore jack up your calorie intake for the day.

So, bottom line is this. Carbs do not make you fat. The only thing that can make you gain weight is a surplus of calories in a day. Carbs may contribute to this surplus, although fats and protein can as well.

 

Carbohydrates and Tiredness

Another misconception is that carbs can make you sleepy, drowsy, or give you brain fog. In fact, the opposite is actually the case. Our brain cells are one of the few cells in our body that are glucose dependent. This means that they can only derive energy from carbs, and not from fats or protein [2]. Therefore, if you are feeling sleepy or tired, it is likely not a result of eating carbs. Eating a few more carbohydrates may actually resolve these symptoms if you are eating a low carbohydrate diet. Some other factors that may be contributing to this is poor-quality or a low amount of sleep, or increased stress (either mental or physical).

 

Carbohydrates and Energy

In this section, I am specifically referring to carbohydrates’ role in sports performance. There are two different ways we can look at energy production in sports: fast, powerful movements such as a jump, sprint, or back squat; or longer distance, endurance activities such as a 5k run.

Carbohydrates are primarily stored in your muscles in the form of glycogen. When we are performing high intensity exercise, such as weight lifting or sprinting, this glycogen is the preferred source of energy. Without it, we would feel much more sluggish and weak in our training. Also, apart from improving sports performance, having sufficient carb stores can help prevent complications such as cramps or heat exhaustion [3].

Carbohydrates are also very important for longer distance, endurance oriented endeavors. One of the main indicators of true physical fatigue is having these glycogen stores depleted. One of the main adaptations with cardio is making these stores last longer, however having a sufficient intake of carbohydrates before you exercise is crucial to making you last longer and perform better [4].

The bottom line is this: for sports performance, carbohydrates are absolutely vital. They are arguably the most important macronutrient to get enough of to perform optimally. How many carbs you should eat in a pre-workout meal is talked about in more detail here.

 

Carbohydrates and Inflammation

This is the last carbohydrate misconception we will talk about. It is commonly said that carbs, specifically sugary foods, can contribute to increasing inflammation in the body. However, the body of research shows that this is really not the case, and that carbohydrates themselves do not increase systemic inflammation [5]. In fact, low glycemic carb sources have even been shown to help reduce inflammation. This is likely because of the fiber content they generally have.

The only time that carbs may increase inflammation in your body is if they put you into a surplus of calories for an extended period of time, causing you to gain an excess of adipose tissue (body fat). This is because this tissue releases molecules called adipokines, which act as a low-level inflammatory signal. Even though this is a low-level signal, it can turn into a big signal when there is an excess amount of body fat. If this is the case in an individual, then the best course of action would likely be to lower body fat, but not specifically lower carb intake [5].

 

Conclusion

So overall, carbs really do not need to be something to be feared or have anxiety over. They don’t make you fat, they don’t make you sleepy, they are absolutely crucial for any athletic endeavor, and high fiber sources of carbs may even help reduce inflammation in your body.

References

1. Does high-carbohydrate intake lead to increased risk of obesity? A systematic review and meta-analysis

   • PubMed ID: 29439068

2. Sugar for the brain: the role of glucose in physiological and pathological brain function

   • PubMed ID: 23968694

3. Carbohydrate Nutrition and Team Sport Performance

   • PubMed ID: 26553494

4. What Should I Eat before Exercise? Pre-Exercise Nutrition and the Response to Endurance Exercise: Current Prospective and Future Directions

   • PubMed ID: 33198277

5. Low-grade inflammation, diet composition and health: current research evidence and its translation

   • PubMed ID: 26228057