September 21, 2021

Nutrition     |     Deidre Bloomquist     |     09/20/2021

At a glance

When it comes to athletic performance, you might be curious how many carbs you really need in your diet in order to fuel your body, recover well, and still reach body composition goals. Knowing that carbs are converted into fat in the body when consumed in excess, some athletes lean towards a Ketogenic diet or low-carb approach, while others rely heavily on steady carb intake in the form of a high-carb diet to fuel their athletic performance. 

So which is right for you? 

high-Carb vs Low-Carb diets

Implementing the right diet is a key strategy to perform your best.  To decide on the best carb intake to reach your goals, it’s important to understand that low-carb and high-carb diets are utilizing different energy sources, especially when it comes to exercise. There’s also no one-size-fits-all approach for athletes, since we are bio-individual and tolerate carbohydrates in particular very differently. What works for your toughest competitor may not actually work for you.

Low-Carb Diets

A low carb-diet focuses on carb restriction by focusing on the other macronutrients available for energy use, but doesn’t necessarily mean that you’re in ketosis or following a ketogenic diet. When considering a 2,000 calories diet, a low-carb diet means that between 10-30% of the overall caloric intake for a day is followed, equating to between 50 and 150 grams of carbs.

The Ketogenic diet

A ketogenic diet on the other hand requires 50 grams of carbs of less on a daily basis in order to achieve a ketogenic state. This will vary from person to person, but in general those following a ketogenic diet require much lower carb intake levels than those following a general low-carb diet, keeping in mind that that standard American diet relies primarily on carbs for caloric intake, with 50% or more daily calories coming from carbs. 

In a ketogenic diet, the goal is to achieve a ketogenic state, where the body is no longer utilizing carbs for energy and is instead producing ketones in the liver to be used as the main source of fuel. In this reduced carb state, the body changes to a metabolic state where ketones are the primary energy source. The only way to know if you are truly in a ketogenic state is through blood, urine, or breath tests to look for the presence of ketones being excreted by the body.

benefits of a Low-carb diet

Both of these models follow the ideology of keeping insulin levels low to avoid an insulin resistant state. When we consume carbs, the body releases a hormone called insulin to shuttle the glucose from the bloodstream to the cells to be used as the primary energy source in the body. When this is done excessively, the cells become resistant to insulin, forcing the glucose in the bloodstream to find a new home. This typically results in the conversion of glucose to body fat to be stored in adipose tissue, making low-carb diets popular among those looking to decrease their overall body fat, as well as reduce the effects of insulin resistance such as fatigue, irritability and shakiness between meals, and promote stable energy levels throughout the day. 

Low-carb diets are particularly beneficial for aerobic exercises that are monostructural, such as running. Aerobic exercise relies very little on carbohydrates for energy, and therefore a low-carb diet may actually prove beneficial for improvements in athleticism.   

Whether you’re following a ketogenic diet or a low-carb diet, ensuring that your protein powder aligns with your goals will be crucial for hitting your daily restricted carb goals. Sources such as Grass-Fed Whey Protein provides 20 grams of protein with only 3 grams of carbs per serving to ensure you are able to meet your protein goals without added sugars.

High-carb Diets

High-carb diets focus on a steady stream of carbs in the diet as they play an important role in the energy pathways used during physical activity for a wide range of fitness models, including weight lifting and HIIT/CrossFit. 

The primary energy source for muscles is glycogen, which is stored in both muscles and the liver, and is done so through the consumption of carbohydrates. During physical exercise, we rely on these glycogen stores to provide energy for muscles to function. When these glycogen stores are depleted in the muscles, we begin to experience muscle fatigue as they no longer have the energy available to continue movement.

benefits of a high-carb diet

High-carb diets are essential for strength training. Many athletes are able to maintain high volume training while on a low-carb diet, but are unable to complete low-rep, heavy weight training without the presence of adequate carbs in the diet to fuel muscles, as well as promote recovery. 

The same is true for HIIT or CrossFit style workouts where muscle glycogen stores can become depleted very quickly. Short interval sprints of effort, moving quickly and moving heavier weights, provides a unique environment to deplete glycogen stores quickly.

But what about insulin levels?

Insulin Levels for Athletes

Insulin is actually required to build muscle cells. When insulin binds to the receptors of muscle cells, they are signaled to make more protein which is then turned into muscle fibers. Without insulin, this muscle building process does not happen. This means that stimulating the release of insulin post-exercise leads to improvements in muscle mass (and strength), and research shows that the optimal ratio of carbs to protein post-workout for these purposes is 2:1

It’s also important to note that the body becomes insulin sensitive post-workout and is better equipped to handle insulin to provide glucose to cells, and does not store glucose as body fat under these conditions.

Carbohydrates for Athletes

So which is right for you? 

As is always true with nutrition, your needs will be unique to you and your goals. If you are weightlifting or training in CrossFit, you’ll need carbs as a fuel source to avoid glycogen depletion and be able to perform optimally. If you’re a runner, a low-carb diet may actually be beneficial since carbs play a small role in athletic performance in aerobic capacity alone.  

Your goals will also be important for determining what’s best for you. If you’re unable to exercise, low-carb may be best for you to promote healthy insulin levels and avoid insulin resistance. If your blood sugar is already in a troubled state, then low-carb may also be beneficial for reserving these effects. If you exercise regularly, your risks for insulin resistance decrease drastically. At the same time, if your goal is to lose body fat, low-carb might be the better option, while those focused on building strength and athletic performance will require more carbs in order to be successful.

Deidre Bloomquist 

Functional Nutritionist based in Denver, Colorado. Certified L3 CrossFit Trainer who loves working with athletes on performance and health goals.  

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