Among middle-aged men who lift weights and are eating fewer calories, a ketogenic diet that keeps ketones high does not lead to better preservation of muscle strength or body composition than a...
Mechanism
Synthesis from 1 study
When middle-aged lifters eat fewer calories and get enough protein, their bodies lose fat and keep muscle the same whether they’re in ketosis or not — the key is how little they eat and how much protein they get, not whether their blood has high ketones, as shown in 10.1016/j.clnu.2021.02.028.
Most probable mechanism
When middle-aged men who lift weights cut calories, their bodies burn fat for energy whether they eat keto or just low-carb, and as long as they get enough protein, their muscles don’t shrink any more on one diet than the other — both diets work the same way because the key factors are how few calories they eat and how much protein they get, not whether their blood has high ketones.
Calorie restriction creates a consistent energy deficit that drives fat mobilization and oxidation in both ketogenic and non-ketogenic low-carbohydrate, high-fat diets, as observed in the same population of resistance-trained middle-aged men.
Protein intake is maintained at similar levels across both dietary groups, preserving muscle protein synthesis rates and minimizing lean mass loss during energy deficit, as measured in the same trial.
Sustained ketone levels above 1 mmol/L do not enhance fat oxidation, muscle protein retention, or strength preservation beyond what is achieved by calorie restriction and adequate protein intake alone, as no additional benefit was observed in the ketogenic group compared to the non-ketogenic low-carb group.
Evidence from Studies
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