Why Going Keto Isn’t Beneficial for High-Performing Athletes

In recent years, the ketogenic diet has surged in popularity. Touted for its benefits in weight loss, blood sugar control, and mental clarity, it’s no wonder so many people have jumped on the low-carb, high-fat bandwagon. But when it comes to high-performing athletes—those who demand explosive energy, rapid recovery, and peak performance—keto may not be the silver bullet it’s often advertised to be.

In fact, for most elite athletes, going keto can actually be counterproductive. Here's why.

1. Carbs Are the Body’s Preferred Fuel for High-Intensity Exercise

During high-intensity workouts—like sprinting, weightlifting, or intense intervals—your body primarily relies on glycogen, a form of stored carbohydrate, for quick energy. On a keto diet, glycogen stores are significantly reduced due to low carb intake. This can lead to early fatigue, slower sprint speeds, and reduced power output.

Bottom line: Without adequate carbs, you’re running your performance engine on fumes.

2. Slower Recovery Times

Carbohydrates don't just fuel your workout—they also fuel your recovery. Post-exercise, your muscles need glycogen to repair and rebuild. A carb-rich diet helps replenish those stores quickly, leading to faster recovery and better training consistency.

Athletes on keto often report feeling sore for longer, and many experience a drop in training volume over time due to incomplete recovery.

3. Reduced Anaerobic Capacity

Anaerobic capacity—the ability to perform short bursts of high-intensity work—is a key component of performance in sports like football, basketball, CrossFit, and sprinting. Keto-adapted athletes often show a measurable decrease in this capacity. The reason? Fat metabolism simply can't keep up with the rapid energy demands of anaerobic effort.

4. Decreased Hormonal Balance and Mood

Extreme low-carb diets can interfere with hormone production, especially in athletes with high energy expenditure. Cortisol (the stress hormone) may increase, while levels of testosterone, thyroid hormones, and even serotonin can drop. The result? Mood swings, poor sleep, and suboptimal recovery.

Athletes need more than just macronutrients—they need balance. And cutting carbs can tip that scale in the wrong direction.

5. Performance in the Lab ≠ Performance on the Field

Some studies have shown that endurance athletes can adapt to keto and maintain steady-state performance over long periods. But adaptation can take weeks or months—and even then, results vary widely. For high-performing athletes who need consistent, top-level performance across a wide range of intensities, that risk isn’t worth it.

And while keto might help with fat oxidation, most sports aren't about conserving energy—they're about explosive bursts, quick decisions, and sustained intensity.

When Might Keto Be Useful for Athletes?

There are a few exceptions. Keto may be beneficial for:

• Ultra-endurance athletes (like ultra-marathoners or long-distance cyclists) who perform at lower intensities over long durations.

• Athletes with specific medical conditions (e.g. epilepsy).

• Off-season fat loss goals, but only temporarily and with careful supervision.

  
  

Final Thoughts: Don’t Sacrifice Performance for a Trend

Athletes aren't average people. Their nutritional needs are greater, more specific, and tightly tied to performance. While keto can work wonders for the general population looking to shed a few pounds, it falls short for those pushing their bodies to the limit.

If you're a high-performing athlete, think twice before cutting carbs. Your performance, recovery, and longevity in sport may depend on it.

Need help optimizing your nutrition for peak performance? Book a free consult call with me today to create a custom plan that fuels your training and gets real results.