The ketogenic diet is definitely a commitment whether you’re an athlete or not.

Experts typically recommend that followers ease into exercise when beginning the diet in order to stave off fogginess or injuries…

But what exactly is the protocol for athletes?

In this article,

We’ll discuss which type of athlete can benefit from the keto diet, which can’t, and the ways in which it can affect them.

When The Keto Diet DOESN’T Work For Athletes

The ketogenic diet is about your body using healthy fats and proteins for energy instead of glucose from carbohydrates.

Less glucose means that your body will use ketones for energy based on the healthy fat intake.

The standard keto diet consists of the following macro ratio: 75% fat, 20% protein, 5% carbs.

With this dietary lifestyle comes a variety of health benefits, from weight loss [1], to helping with conditions like epilepsy [2].

With that said,

There are circumstances for athletes where the ketogenic diet is not an optimal choice.

Athletes who partake in high-intensity workouts or sports might suffer in their performance on the keto diet. These include activities like:

  • Soccer
  • Basketball
  • Sprinting
  • HIIT training
  • Many types of aerobic activities


Researchers have tested keto’s effects on endurance athletes vs. high-intensity sprint athletes.

The latter demographic did not perform well at anaerobic exercise tasks – overall, lower than the endurance athletes. Fatigue was also prevalent in the high-intensity athletes.

Short, high-intensity exercise depends highly on glycolysis – the breakdown of glucose, for energy. The keto diet uses fat for energy rather than glucose.

Further research shows negative results for athletes using keto. Increased amounts of free fatty acids as well as ammonia were seen in the bloodstream during the workout.

This contributes to an impaired metabolism and fatigue in the central nervous system. Without long-term adoption, an athlete could possibly experience reduced muscle glycogen, hypoglycemia, and stilted athletic performance.

When The Keto Diet DOES Work For Athletes

So, which kind of athletes can handle keto the best?

After an adoption period, endurance athletes fare better on the keto diet than ‘sprint’ athletes and people who follow high carbohydrate, low-fat diets. This means sports like:

  • Cycling
  • Running/jogging
  • Dancing
  • Swimming
  • Brisk walking
  • Climbing stairs at work
  • Tennis

One reason is that it does take time to adjust to the keto diet (anywhere from several weeks to months), which coincides with an endurance athlete’s lifestyle.

Other reasons are that the keto diet helps control body weight, reduce fat, maintain muscle mass, and help people feel fuller more quickly.

People on low carb diets find that their hunger levels are suppressed for longer periods of time, and they no longer want to gorge extra calories.

Endurance athletes on low carb, high-fat diets are more prone to burn fat efficiently than low-fat, high-carb dieting athletes. Endurance athletes who stick with the keto diet for 9-36 months reach optimal fat burning than those who are on high-carb diets.

What about athletes with type 2 diabetes?

Studies have shown that keto helps reduce type 2 diabetes, excess body fat, and metabolic syndrome.

One particular study examined finding alternate solutions to Type 2 diabetes (T2D) apart from a reduced fat diet and glucose-lowering medications, which often promotes weight gain.

238 adults with an average age of 54 were given a keto diet over a 10-week period. By the end, over half of the adults had eliminated or reduced the glucose-lowering medications, and it was effective in improving glycemic control and weight loss efforts as well [3].

Tips For Athletes On Keto

Athletes who decide to take on the ketogenic lifestyle need to exercise caution.

Though keto is acceptable for endurance athletes, there are still the same risky side effects. These changes to your body can also result in the “keto flu“.

These include symptoms like:

  • Fogginess/dizziness/feeling weak
  • Headaches
  • Gastrointestinal symptoms like diarrhea or constipation.
  • Back pain
  • Irritability
  • Concentration issues

It’s safe to say that keto can be effective for endurance athletes but only after an adoption period.

Ironically, recreational athletes might see better results than competitive athletes because the former are more focused on weight loss and health rather than just competition.

If you are more of a recreational athlete, try to find light exercises like walking or yoga.

For athletes, it’s very important to consume sufficient healthy fats, more so than protein.

Too much protein can cause the body to convert the excess proteins into sugar through a process called gluconeogenesis. This has the potential to kick you out of ketosis.

In any case, the following are some suggestions for a healthy, sustainable meal for athletes:

  • Breakfast: Scrambled eggs with avocado and a slice of fruit.
  • Lunch: Salad with chicken breast, avocado, oil and vinegar dressings, beans, and a little almond butter.
  • Snacks: macadamia nuts.
  • Dinner: Fish, a small portion of whole grains, and a cup of broccoli.

Check out: The Ultimate Keto Breakfast! A Macro-Friendly, Low-Carb Meal


It’s generally recommended that those starting out on the keto diet consult with a doctor or dietician, but this is especially true for athletes.

Professionals can help guide you or even put together a plan on how to optimally leverage the keto diet for your athletic performance. They can also dissuade you from trying this diet if they feel it’s too risky or restrictive.


The keto diet can be feasible for athletes after taking the right precautions, but it isn’t advisable for people who participate in high-intensity interval sports.

For endurance athletes, it can be effective after an adoption period, but again, always consult with a doctor or dietician to make sure you’re following a lifestyle that is safe and healthy.

[1] Nymo S, Coutinho SR, Jørgensen J, et al. (2017) Timeline of changes in appetite during weight loss with a ketogenic diet. Int J Obes (Lond) 41, 1224–1231. [PMC free article] [PubMed]

[2] Hemingway C1, Freeman JM, Pillas DJ, Pyzik PL. The ketogenic diet: a 3- to 6-year follow-up of 150 children enrolled prospectively. Pediatrics. 2001 Oct;108(4):898-905.

[3] McKenzie, PhD and others. “A Novel Intervention Including Individualized Nutritional Recommendations Reduces Hemoglobin A1c Level, Medication Use, and Weight in Type 2 Diabetes.” JMIR Publications, July 3rd, 2017.