Low-carb diets enhance athletic and mental performance
the verdict
REFUTED
the evidence says no
confidence 23/100
While low-carbohydrate and ketogenic diets successfully increase fat oxidation and aid in weight management, robust scientific evidence demonstrates that they do not enhance athletic performance and frequently impair high-intensity or endurance output.
Evidence for · 1
Metabolic characteristics of keto-adapted ultra-endurance runners
2015 · cited by 310
Long-term keto-adaptation in ultra-endurance runners results in extraordinarily high rates of fat oxidation while maintaining similar muscle glycogen utilization.
Evidence against · 4
Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers
2016 · cited by 404
Adaptation to a ketogenic low-carbohydrate, high-fat diet impairs performance in elite endurance athletes due to reduced exercise economy.
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More against · 3
Ketogenic diet benefits body composition and well-being but not performance in a pilot case study of New Zealand endurance athletes
2017 · cited by 83
Endurance athletes undertaking a 10-week ketogenic diet experienced significant performance decrements, such as reduced time to exhaustion and inability to easily undertake high-intensity bouts.
The Effects of a Ketogenic Diet on Anthropometric Parameters, Metabolic Adaptation, and Physical Fitness Performance in Amateur Endurance Athletes: A Systematic Review
2021 · cited by 2
A systematic review concluded that although ketogenic diets can induce anthropometric and metabolic changes, they do not improve amateur endurance athletes' performance.
The Impact of the Ketogenic Diet on Athletic Performance: A Systematic Literature Review
2025 · cited by 1
Recent literature indicates that while the ketogenic diet may promote weight loss, it does not consistently improve aerobic capacity, strength, or speed, and can lead to performance declines.