Low-carbohydrate, high-fat diets may help endurance athletes perform better, but team and sprint athletes may see a drop in their performance.
Ketogenic diets are not just for losing weight. Many endurance athletes also turn to these very low-carb, high-fat diets to boost their performance.
But athletes involved in high-intensity, short-duration sports might see drops in performance while on a ketogenic diet, suggests new research.
Researchers from Saint Louis University tested the anaerobic exercise performance of 16 men and women following either a low-carbohydrate ketogenic diet or a high-carbohydrate diet for four days.
People on the ketogenic diet performed more poorly at anaerobic exercise tasks than those eating more carbs.
Depending on the task, their performance was 4 to 15 percent lower than the high-carbohydrate group.
The study was published last month in the Journal of Sports Medicine and Physical Fitness.
Study author Edward Weiss, PhD, associate professor of nutrition and dietetics at Saint Louis University, said that the results could make a big difference to athletes involved in sports that depend on short-burst anaerobic activities.
This includes sprint-type activities that occur in soccer and basketball and also short, intense activities like the 100-meter sprint and the triple jump.
Weiss added that the study “probably also applies to many aerobic activities, as other studies have demonstrated that high-intensity aerobic exercise performance may be compromised by low-carb diets — including keto.”
In light of these results, he advised athletes to avoid these diets unless they have “compelling reasons for following a low-carb diet.”
While this is a small study and people were on the two diets for only a few days, a 2017 review of previous research found similar early onset fatigue during short-duration activities while on a ketogenic diet.
Weiss said that additional studies will provide more insight into the pros and cons of ketogenic diets for athletic performance. For now, he suggests that athletes “err on the cautious side.”
Endurance athletes such as marathon runners and long-distance cyclists might fare better on a ketogenic diet than…