With the exploding popularity of low-carb or Ketogenic diets, even athletes are beginning to wonder if they, too, should avoid carbs. While carbohydrates have long been considered the athlete’s best friend, now the focus is more on protein and a well-rounded diet to build strong bodies. But do high-fat, moderate protein diets really support high-performance lifestyles? Is going low-carb actually safe for athletes? And is the solution for the perfect athletic diet as simple as piling on or laying off the grains and starches?

At PH2 Nutrition, I have worked with numerous athletes, body builders, as well as champion and record holding endurance athletes such as: swimmers, runners, triathletes, rowers, and cyclists. These clients are not looking just to be healthy. Regardless of their ability level, they are looking to be OPTIMAL so they can train smarter, recover faster, and increase their performance. This trend of low carb diet works for people looking to get healthier, but is it for athletes?

First, it’s important to clarify that when it comes to nutrition, we are all unique there is no one-size-fits-all answer. If you’re hoping to find a diet that best matches your lifestyle, genetics, goals, you should talk to a nutrition counselor who can match you with a routine that complements the unique needs of your body. 

That said, there are some things that sports nutritionists can agree on that have been proven to be successful. Here are the basics to help clarify the relationship between carbohydrates and an active lifestyle.


Low-carb diets have been a successful weight loss option for a lot of people in recent years.  Of course, due to the lack of knowledge of how to properly low carb diet, or be in ketosis, the long-term results are mixed. In the past, some of the more extreme low-carb diets prove to be unsustainable as the dieter inevitably regains the weight.  We have learned how to sustainably give people low carb diets but have also learned that it is not suitable for everyone, about 30% of the population who are insulin resistant. Others find long-term weight control easy with a plan that includes carbohydrates. Either way, it’s important to realize that people who get the most out of low-carb plans are people who have very different genetics, goals, and lifestyles.

Simply put, both athletes and non-athletes can be in a low carb situation if it is beneficial to their body type which we can find out by testing and blood results. 

However, athletes have a greater priority: performance. 

If an athlete avoids carbs, will they discover improvement in endurance, muscle recovery, and mental clarity, as well? Some professionals have theorized that high-fat, low-carb diets can improve performance in the long run. However, study after study has demonstrated that carbohydrates are still essential to athletic excellence.  And despite low-carb fanaticism, the world’s greatest athletes continue to rely on high carbohydrate intake.

Here is why.


In order to understand why athletes, in general, should not avoid carbs, you must first understand what carbohydrates actually do.

Out of the three different macronutrients- proteins, fats and carbs, only two of those are actual energy sources-fats and carbs. Proteins are used for the building blocks of the body such as tissues, enzymes, hormones, cells among many other things.  If you are not eating enough, your body can break down muscle for energy which is not ideal.

When you are low carbohydrate but eating high fat and protein, your body goes into ketosis, which is the conversion of your fat molecules into ketones that are used for energy.  However, the process of changing fat into ketones is slow and does not give you the quick access to energy that you may need during a workout or race.

When you consume carbohydrates, they are broken down into glucose. Your body stores glucose as glycogen in your liver and in your muscles to be used for fuel. As you engage in physical activity, the glycogen stores in your muscles gradually run out. So, if you’re an athlete who engages in long training sessions or high-intensity workouts, you need more carbohydrates. Otherwise, your glycogen stores become depleted. The result is muscle fatigue.

But endurance isn’t the only reason athletes shouldn’t avoid carbs.  Since converting fat to ketones is a process that takes longer than using carbohydrates, your body may turn to breaking down muscle proteins and converting them to a usable source of energy.  Protein is not typically used as an energy source and this is a major downside for athletes.  Protein exists to repair injured muscles and support muscle growth. If you want to get stronger and recover quickly from a high-intensity workout, you need to consume an adequate amount of carbs.  That way your body chooses glucose as its primary energy source, freeing protein to rebuild muscle.

One of the misconceptions of ketosis is that you are losing weight because you are burning fat for energy.  However, when you are low carb you are also eating more fat. The goal of low carb, or ketosis, is to reduce your insulin resistance which can cause excess sugars in the body being stored as fat. The goal of any PH2 program is to eat the correct amount of calories, whether that be from high carb or high-fat diet because when you have a steady pattern of anti-inflammatory foods, you will not store excess fat.  When your insulin is down, your cortisol also goes down which is responsible for also causing you to hoard.

An athlete may benefit from a ketosis diet to reduce insulin resistance due to his DNA but in general, because athletes are less sedentary than regular people, they will benefit from being in a carbohydrate diet for the quick energy to sustain activity.


As any athlete knows, mental clarity is just as important as physical endurance when it comes to excellence in sports. Which means it would be better to not skip the carbs.

The brain uses glucose from carbohydrates to produce energy. When you cut yourself off from carbs, you cut your brain off, too. The brain needs glucose to synthesize acetylcholine, a key neurotransmitter. Otherwise, your performance suffers and your memory suffers. In short: you can’t stay alert and sharp on any playing field when your body is forced to work off of fat alone.


If you’re an athlete, your nutritional plan should be as finely tuned as your training routine. Your performance depends significantly on what you put into your body and when you consume it. This is why simplistic diets designed specifically for weight loss alone are not the best option for you. Your responsibility as an athlete is to maintain a proper macronutrient balance and a consistent dietary routine.

Rather than avoiding carbs, consume them intelligently.

First, understand the difference between simple carbohydrates and complex carbohydrates. Simple carbohydrates are more processed and easier to digest. This means that when you need to reload those glycogen stores, simple carbohydrates get the job done quickest. Think fruits, milk, energy bars, white bread, pasta, low-fiber cereal, and sugary snacks.

Complex carbohydrates are high in fiber and nutrients. They are much harder to break down and are found in foods such as whole grains, vegetables, and beans.

 Your best course of action is to choose simple carbs before and during training. Then, prioritize complex carbohydrates at the end of the day when your body is resting and no longer needs an immediate burst of energy.  Another great rule of thumb is to eat hearty in the morning and mid-day, then choose a smaller meal for dinner.  Dinner is a great time to choose complex carbohydrates.

Of course, the question of whether or not to avoid carbs is only one aspect of sports nutrition. Food timing, supplements, pre, and post-workout protocols are only some of the other things to add to your training. If you’re really hoping to design a dietary routine that supports your lifestyle, you should talk to a professional. At PH² Nutrition, we take the time to learn your health history, goals, and unique physical needs. That way, we can set you up with the dietary plan that emphasizes performance and health. If you’d like to learn more, please drop us a line.

Either way, we wish you the very best in health and performance.