Endurance athletes are a unique breed. And their specific energy system used during exercise requires them to eat differently than their peers.
They also need to maintain adequate levels of electrolytes before, during, and after exercise—and thus, need the support of proper supplements.
As a sports nutritionist and functional medicine practitioner, I work with both competitive and amateur endurance athletes. Let’s take a closer look at what endurance athletes need to know about proper nutrition and supplementation.
While “carb-loading” has long been synonymous with endurance athletes and nutrition, a diet low in carbs and high in fats — such as the keto diet — has proven advantages for performance athletes.
For example, marathon runners who burn ketones instead of glucose experience increased cognitive and physical performance. The brain operates better on ketones than glucose from sugar or carbs, leading to heightened levels of concentration and longer periods of focus.
Physically, keto-adaptation — the body’s transition to burning fat instead of glucose for energy — improves endurance exercise capacity in athletes, as well as improving fat mobilization and oxidation during exercise performance.
Keto-adaptation also improves aerobic and anaerobic exercise capacity in endurance athletes.
The keto diet minimizes the breakdown of lean muscle tissue and increases the body’s ability to maintain lean body mass while burning fat, which is beneficial for performance athletes’ body composition.
Additionally, ketones increase mitochondrial glutathione levels, subsequently feeding the mitochondria better and leading to more rapid recovery between exercise sessions.
The greatest physical outcome of keto-adaptation for athletes is improved endurance during competition. Performance athletes such as ultra-runners or soccer players who are keto-adapted will experience increased endurance and less central fatigue during the course of their competition or match.
On the keto diet, the body taps into slow-burning fat storage, which prevents athletes from “hitting the wall.” This is especially beneficial to those athletes who can’t easily digest foods while exercising (e.g. a tennis player between sets).
During keto-adaptation, liver and muscle glycogen deposits are maintained, attenuating the glycogen depletion observed in athletes consuming high-carbohydrate diets. With the absence of glucose to burn, athletes won’t experience the peaks and valleys of varying blood sugar levels.
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