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The ketogenic diet has been popular for several years now, as its hailed for limiting carbohydrates and upping fat What Is a Shoey weight loss.
If you’re looking to change up your eating habits this year, you may be wondering if the keto diet is right for you—and can it help your run performance?
To get to the bottom of the pros and cons of the keto diet for runners, we talked to dietitians to get the full scoop. Here’s what to know before you swap all the carbs for all the fats.
What is the keto diet?
The ketogenic diet (or keto diet) sets very strict guidelines on how to break down your macronutrient (carbohydrate, protein, and fat) intake. Those following keto consume 80 percent of their calories from fat, 15 percent from protein, and 5 percent of calories from carbohydrates—the fuel source your body and brain prefer to tap first as it’s the fastest and most easily accessible.
We may earn commission from links on this page, but we only recommend products we back, eggs, dairy, oils, and body, says pasta, rice, potatoes, and fruit are off-limits.
Here’s how the keto diet works: When your body no longer has access to fuel from carbohydrates—either because they’ve been cut from your diet or you haven’t eaten in a long time—it goes into a state called ketosis. That means, your body looks for the next best fuel source: fat. And it uses the available fatty acids to produce a compound called ketones, which is why people who are in ketosis and eating more fat will start to burn more fat.
The ketogenic diet is not to be confused with a low-carb high-fat diet, which is similar. The difference is the keto diet aims to increase the ketone levels in your blood, causing your body to enter ketosis.
What are the benefits of the keto diet?
While our bodies prefer to feed on carbohydrates, ketones can actually fuel the brain actually fuel the Lizzie Kasparek, The Benefits of Spirulina Sanford Sports Science Institute. So it’s not like you’re depleting your body in a dangerous way.
“Being in ketosis does not imply reduced muscle glycogen levels. Over time, the keto-adapted athlete may improve his or her ability to burn fat for fuel and still have glycogen available,” says Kenneth Ford, Ph.D., director and CEO of the Institute for Human and Machine Cognition. (As long as the athlete carb loads.)
Whether runners, specifically, should put their bodies in a state of ketosis depends on your goals—and the verdict is still out on whether it really helps with performance. Most studies on keto and athletes involve only a small number of participants and most researchers say we need more studies on the topic.
For example, Nutrition & Weight Loss of five endurance athletes, published in the Journal of the International Society of Sports Nutrition, showed that a 10-week keto diet improved the athletes’ body composition and well-being but not their performance. In fact, the athletes initially experienced reduced energy levels Foods High in Vitamin E That Boost Recovery.
Another small study in the journal Guide to Healthy Fats looked at the effects of the keto diet on exercise efficiency in eight trained athletes. After following the diet, the athletes saw a decline in running speed and power—running speed at VO2max declined by 5 percent.
Other research, including a review of seven articles on the subject, says that there’s limited findings on the benefits of keto for endurance athletes and results are mixed when it comes to VO2 max and other performance outcomes.
What are the downsides of the keto diet?
“There isn’t really a lot of good research that shows those people can perform better, and that’s really what runners care about,” Kasparek says.
Ford also points out that in the studies looking at ketosis and performance with negative results, the athletes are not often sufficiently fat-adapted (when the body is trained to tap fat stores for energy, which can take several months) or even in ketosis, making it hard to truly gauge whether the diet is effective when it comes to performance. Also, performance generally involves an athlete exercising at a relatively high intensity, which requires carbohydrates as the main fuel source.
and an inability to undertake high-intensity bouts of exercise ultramarathons. Once you hit those later miles, your body relies on fat for energy production.
For everyone else, carbs are still probably your best bet, especially if you’re running at higher intensities than you would be when running 50 miles. When you’re running at a lower intensity, your body is able to burn fat as fuel, Kasparek explains. “But because carbs are the main source of fuel at higher intensities, you may be sacrificing key workouts or your race to follow a certain diet,” she says.
What should you know before you try the keto diet?
So, does the keto diet work and should you try it? The bottom line is: If done right, runners who need to be able to tap into fat stores over long distances may benefit from occasionally eating fewer carbs and relatively more fat around longer, less intense training sessions. A runner does not necessarily need to be in ketosis to follow this type of “carbohydrate periodization.”
Runners who do speed workouts or who enjoy shorter distances at faster paces or who incorporate high-intensity workouts into their training are still better off eating a healthy, balanced diet that includes carbs.
For weight-loss goals, Kasparek says, it’s possible to lose weight by tweaking a regular diet, say, by adding more healthy fat or cutting out processed foods. (And focusing on a calorie deficit.) But there’s more than one way to lose weight, and one banana isn’t going to set you back—we promise.
Exactly What to Eat Before a Marathon Runner’s World, Nutrition - Weight Loss The Runner’s World Vegetarian Cookbook, and a nine-time marathoner with a best of 3:23. She’s also proud of her 19:40 5K and 5:33 mile. Heather is an RRCA certified run coach.
Dr. Namrita Brooke is a full-time endurance sport coach and sport nutritionist advising active individuals and amateurs to professional athletes. She is also an adjunct professor in the Department of Movement Sciences and Health at University of West Florida. Professionally, she also serves on the Board of Editors of the Sports Nutrition Care Manual and remains involved in nutrition and exercise-related research, student mentorship, and coach development. Namrita's personal athletic experience ranges from ultra-endurance mountain biking to off-road triathlon, cross-country mountain bike racing, gravel cycling, duathlon, cyclocross, running, and trail running. Her research background includes hydration and sports drink research, and the interaction of nutrition, physical activity, and the brain.
