What you decide to eat is how you’ll fuel your body throughout the day. While carbohydrates have long been considered the body’s sole source of fuel, studies have shown that ketone bodies are just as effective. What’s more, they don’t create as much metabolic waste as glucose. So how will your workouts be affected on the keto diet?
Ketones provide a variety of health benefits, but how do they stack up against glucose during exercise? Let’s take a look at how the keto diet and running your body on ketones will impact different areas of your workouts.
Keto Flu Will Impact Exercise Performance
Chances are, if you’ve done a bit of research, you know that the keto flu is a common but short-lived side effect for those starting the keto diet. Symptoms of the keto flu include fatigue, brain fog, and less energy, especially during workouts.
That’s not to say you shouldn’t exercise during this time (you absolutely should) but be aware that you might notice a dip in your athletic performance. Once you’re keto-adapted, your performance will return to normal.
High Intensity Performance Might Suffer
Before becoming fat-adapted, you may notice a decrease in high intensity performance. One study found that subjects had less endurance and peak power while succumbing to exhaustion faster.
Something to note is that the study had a small sample size, and not everyone reports being affected the same way. You want to keep this in mind though just in case you’re curious why you had a sudden decline in high-intensity performance. 
Higher Level of Caloric Expenditure (Calorie Burning)
One added benefit of exercising on a keto diet is the natural increase in calorie burning. The ketogenic diet will naturally throw your body’s fat-burning ability into overdrive, which gets magnified during your weekly workouts.
Studies show that subjects burned more fat during a resistance training workout when they were keto-adapted or in a state of ketosis. 
The one thing you don’t have to worry about is losing muscle mass while exercising on a keto diet. Studies show that the ketogenic diet preserves lean muscle tissue, ensuring your hard-earned muscle mass stays safe. 
With that said, if your goal is to be the next Mr. or Ms. Olympia and you want to look like Iris Kyle or Phil Heath, the ketogenic diet won’t get you there. The keto diet isn’t ideal for building a mass monster body. But it could be useful for aesthetic-focused competitions such as the Men’s or Women’s Physique.
Workouts Fueled by Keto
Experiment with different types of exercises to see which one works best for you while on a keto diet. Need help? Check out our OK32 system, which provides you with a step-by-step workout guide to maximize your progress on the ketogenic diet.
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- Durkalec-Michalski, K., Nowaczyk, P.M. & Siedzik, K. Effect of a four-week ketogenic diet on exercise metabolism in CrossFit-trained athletes. J Int Soc Sports Nutr16, 16 (2019). https://doi.org/10.1186/s12970-019-0284-9.
- Paoli A, Cancellara P, Pompei P, Moro T. Ketogenic Diet and Skeletal Muscle Hypertrophy: A Frenemy Relationship?. J Hum Kinet. 2019;68:233–247. Published 2019 Aug 21. doi:10.2478/hukin-2019-0071.
David James Sautter is a fitness writer with over a decade of experience in the industry. After graduating with a Bachelor of Arts in English and Secondary Education, he earned certifications as a NASM-certified personal trainer, NASM-certified fitness nutrition specialist, and ACE-certified sports conditioning specialist. Merging his two passions, he has been the driving creative force behind articles, e-books, and training guides that cover a range of health and fitness topics with an emphasis on the ketogenic diet.