Keto for Athletes: Can It Enhance Performance?

The keto diet for athletes has been a center for discussion due to the carbohydrate restriction. If you’re an athlete wanting to get into the keto diet or are already into the keto diet and want to incorporate workout routines, then this comprehensive discussion is for you.

Key Takeaways:

  • The keto diet has been historically proven to sustain energy levels despite physical activities.
  • The keto diet is more suitable for low to moderate-intensity activities, while variations like the cyclical keto diet are fit for more high-intensity activities.
  • The keto diet helps with fat adaptation, stable blood sugar levels, increased endurance, improved cognitive health and body composition, reduced inflammation, and appetite regulation.

Table of Contents:

Table of Contents

The Keto Diet for Athletes

While it’s true that there is an adaptation phase where the body shifts its energy source from glucose to fat, it’s also proven among generations that being in ketosis and focusing on a keto diet does not impair endurance and performance.

Let’s take into consideration people who naturally and traditionally focus on the keto diet. Traditionally subsisting on a diet rich in fish, marine mammals, and fats, the Inuit1 people have adapted to a low-carb, high-fat lifestyle and have been reported to be healthy.

There are also tribes in Africa and Siberia who are naturally hunters and get their calories mostly from animal sources with no physical limitations to their daily activities.

keto for athletes

Misconceptions About Ketosis for Athletes

There are several misconceptions about ketosis for athletes, especially during the first years of its popularity. However, current scientific research supports the benefits of keto for athletes and bodybuilders.

Here are some of the common misconceptions and discussion on the reality:

  1. Ketosis Equals Ketoacidosis: Nutritional ketosis,2 as induced by the ketogenic diet, is a controlled metabolic state with moderate ketone levels that pose no harm. Athletes can safely enter and maintain nutritional ketosis without the risk of ketoacidosis.3
  2. Inability to Sustain High-Intensity Exercise: While it’s true that glycogen stores are lower on a ketogenic diet, emerging research suggests that well-adapted athletes can still perform at high intensities4 by efficiently utilizing fat as a primary energy source.
  3. Muscle Wasting on Keto: Adequate protein intake on a ketogenic diet and resistance training can support muscle maintenance and growth.5 Keto-adapted athletes can build and preserve muscle effectively.
  4. General Lack of Energy: Once adapted, many athletes report sustained energy levels6 and improved endurance on a ketogenic diet. The body becomes proficient at utilizing ketones, providing a stable energy source.

What Does Exercise Do to Ketone Levels?

Exercise increases ketone levels,7 but the intensity of the increase depends on what type of exercise you do.

During aerobic exercise, such as long-distance running, the body’s increased energy demand prompts the breakdown of fatty acids, elevating ketone production.

However, in anaerobic activities like weightlifting, the reliance on glycolysis may not significantly impact ketone levels. Since the body will spare glycogen stores, the glucose levels will rise, and ketone levels will decrease temporarily.

Moreover, the immediate post-exercise period may witness a dip in ketone levels, but during recovery, levels tend to rise due to increased lipolysis and fatty acid oxidation.

What Are the Benefits of Keto for Athletes?

Despite contrary belief, variations of the keto diet offer benefits even for athletes. Here are the top benefits:

Improved Fat Adaptation:

The ketogenic diet trains the body to rely predominantly on fat for energy by limiting carbohydrate intake. This adaptation increases the efficiency of fat metabolism, allowing athletes to tap into a more abundant energy source during exercise.

Stable Blood Sugar Levels:

By minimizing carbohydrate intake, keto diets contribute to more stable blood sugar levels.8 This stability can lead to sustained energy levels, preventing the performance fluctuations associated with the peaks and crashes of glucose metabolism.

Increased Endurance Performance:

Athletes well-adapted to the keto diet often report increased endurance performance. The efficient utilization of ketones as a fuel source, especially during low to moderate-intensity activities, can contribute to prolonged stamina.

Moreover, the keto diet allows the body to spare and save glycogen more easily, which means it is readily available in high-intensity exercise.4

Potential Cognitive Benefits:

The brain, a significant energy consumer, can benefit from the ketones9 produced during a ketogenic state. Some athletes report enhanced mental clarity and focus, potentially contributing to improved decision-making during competitions.

Fat Loss and Body Composition:

The nature of the keto diet, with its emphasis on fat metabolism, can lead to effective fat loss. Athletes seeking to optimize body composition10 may find the keto diet supportive in reducing body fat while preserving lean muscle mass.

Reduced Inflammation:

Keto diets may exhibit anti-inflammatory effects,11 which can be advantageous for athletes with exercise-induced inflammation. This reduction in inflammation may contribute to quicker recovery times between training sessions.

Appetite Regulation:

The satiating nature of fat-rich meals on the keto diet may contribute to better appetite regulation.2 Athletes can experience reduced cravings and a more consistent energy intake, supporting overall nutritional adherence.

Can Keto Improve Endurance Performance?

Here’s what we’ve cleared out so far: Ketone bodies are an excellent energy source in the absence of glucose, and they are a more stable energy source, meaning the sustenance of energy during exercise is not the issue.

Studies suggest the keto diet may enhance endurance4 for well-adapted individuals by promoting efficient fat metabolism. Moreover, keto variations, such as cyclical keto, cater to athletes’ needs to boost glycogen storage.

During low to moderate-intensity activities, athletes in ketosis can tap into a sustained supply of ketones, potentially reducing reliance on glycogen stores and delaying the onset of fatigue.

However, it’s essential to acknowledge individual variability in keto responses; some athletes may experience an initial decline in performance before adaptation occurs.

Can You Build Muscle on Keto?

Contrary to the belief that the ketogenic diet hinders muscle building, athletes can build and preserve muscle on keto5 with careful planning, especially with the rise of keto variations such as the high-protein keto diet.

While carbohydrates are traditionally associated with promoting muscle growth due to their role in insulin secretion, keto athletes can leverage protein intake and resistance training.

Moreover, the diet’s anti-inflammatory effects may improve recovery, potentially supporting muscle-building efforts.

Lastly, keto-friendly supplements that support muscle growth are becoming more popular with proven benefits, which could help maintain and gain muscle mass.

What Are the Downsides of Keto for Athletes?

While the ketogenic diet presents potential benefits, it also comes with downsides that athletes should carefully consider.

One significant drawback is the initial adjustment period known as the keto flu, characterized by symptoms like fatigue and irritability12 as the body transitions to ketosis, but this is primarily temporary, and some athletes even deny going through this stage.

Additionally, as mentioned, the keto diet is more efficient for low to moderate-intensity activities, as the limited availability of dietary carbohydrates may pose challenges for athletes engaged in high-intensity, short-burst activities that heavily rely on glycogen stores.

Maintaining electrolyte balance becomes crucial, as the diuretic effect of keto may lead to increased fluid and electrolyte loss. Supplementation may be needed.

Can You Workout While Intermittent Fasting?

Yes, working out while intermittent fasting is a feasible and healthy way to maintain overall health. It’s better to work out when fasting so the body can tap into stored fat for energy, promoting fat loss and optimizing metabolic adaptations.

Moreover, intermittent fasting for athletes has proven benefits, such as increased strength and endurance, autophagy, weight management, improved metabolic parameters and body composition, and increased mental clarity and focus.

The Bottom Line

Contrary to mainstream misconception, athletes can still do the keto diet and still benefit from it. While the keto diet is better for low to moderate-intensity activities, those who engage in high-intensity exercises and weightlifting can benefit from the cyclical keto diet.

Frequently Asked Questions (FAQ)

Is the keto diet good for athletes?

Yes, the keto diet offers benefits for athletes, and some variations fit those who engage in high-intensity sports. The keto diet enhances endurance, regulates energy sources, and improves body composition.

Does LeBron James do keto?

Circulating reports state that LeBron James once eliminated sugar, carbs, and dairy in his diet back in 2014, which ultimately transformed his physique. Some reports say he did the keto diet for 67 days.

What famous athletes are on the keto diet?

Aside from LeBron James, some famous athletes who’ve tried the keto diet are Kobe Bryant, Tim Tebow, Shane Watson, and The Parramatta Eels Rugby League Team.

What do keto athletes eat during a race?

Most athletes take MCT oil, high-fat nuts, and high-fat snacks during a race to fuel their energy. They also maintain hydration through electrolyte drinks.


1Hu, X. F., Kenny, T. A., & Chan, H. M. (2018). Inuit Country Food Diet Pattern Is Associated with Lower Risk of Coronary Heart Disease. Journal of the Academy of Nutrition and Dietetics, 118(7), 1237–1248.e1.

2Gershuni, V. M., Yan, S. L., & Medici, V. (2018). Nutritional Ketosis for Weight Management and Reversal of Metabolic Syndrome. Current nutrition reports, 7(3), 97–106.

3Ghimire P, Dhamoon AS. Ketoacidosis. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:

4Cipryan, L., Plews, D. J., Ferretti, A., Maffetone, P. B., & Laursen, P. B. (2018). Effects of a 4-Week Very Low-Carbohydrate Diet on High-Intensity Interval Training Responses. Journal of Sports Science & Medicine, 17(2), 259-268.

5Vargas-Molina, S., Gómez-Urquiza, J. L., García-Romero, J., & Benítez-Porres, J. (2022). Effects of the Ketogenic Diet on Muscle Hypertrophy in Resistance-Trained Men and Women: A Systematic Review and Meta-Analysis. International Journal of Environmental Research and Public Health, 19(19).

6McSwiney, F. T., Doyle, L., Plews, D. J., & Zinn, C. (2019). Impact Of Ketogenic Diet On Athletes: Current Insights. Open Access Journal of Sports Medicine, 10, 171-183.

7M. Pinckaers, P. J., Churchward-Venne, T. A., & Bailey, D. (2017). Ketone Bodies and Exercise Performance: The Next Magic Bullet or Merely Hype? Sports Medicine (Auckland, N.z.), 47(3), 383-391.

8Dowis, K., & Banga, S. (2021). The Potential Health Benefits of the Ketogenic Diet: A Narrative Review. Nutrients, 13(5).

9Altayyar, M., Nasser, J. A., Thomopoulos, D., & Michael Bruneau, J. (2022). The Implication of Physiological Ketosis on The Cognitive Brain: A Narrative Review. Nutrients, 14(3).

10Cipryan, L., Dostal, T., Litschmannova, M., Hofmann, P., Maffetone, P. B., & Laursen, P. B. (2021). Effects of a Very Low-Carbohydrate High-Fat Diet and High-Intensity Interval Training on Visceral Fat Deposition and Cardiorespiratory Fitness in Overfat Individuals: A Randomized Controlled Clinical Trial. Frontiers in Nutrition, 8.

11Masino, S. A., & Ruskin, D. N. (2013). Ketogenic Diets and Pain. Journal of Child Neurology, 28(8), 993.

12Batch, J. T., Lamsal, S. P., Adkins, M., Sultan, S., & Ramirez, M. N. (2020). Advantages and Disadvantages of the Ketogenic Diet: A Review Article. Cureus, 12(8).

Mag. Stephan Lederer, MSc.

Mag. Stephan Lederer, MSc. is an author and blogger from Austria who writes in-depth content about health and nutrition. His book series on Interval Fasting landed #1 on the bestseller list in the German Amazon marketplace in 15 categories.

Stephan is a true man of science, having earned multiple diplomas and master's degrees in various fields. He has made it his mission to bridge the gap between conventional wisdom and scientific knowledge. He precisely reviews the content and sources of this blog for currency and accuracy.

Click on the links above to visit his author and about me pages.

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