Research
Mixed
Ketogenic diets may lead to a loss of fat-free mass (FFM) in resistance-trained individuals, whereas they preserve FFM more effectively in endurance-trained individuals compared to resistance training.
If you lift weights, be aware that a ketogenic diet might cause you to lose some muscle mass. If you do endurance sports, you might preserve muscle better. Monitor your strength and adjust protein intake if you notice performance or muscle decline.
ModerateQualifiesMEDIUM confidence
In terms of lean mass, it seems that following a KD can cause FFM loss in resistance-trained individuals. In contrast, the FFM-preserving effects of KD are more efficient in endurance-trained compared with resistance-trained individuals.
Why this rating
Based on review of specific subgroups; evidence is described as 'seems' and 'inconclusive' in parts.
Source
Ketogenic diets, physical activity and body composition: a review
Damoon Ashtary‐Larky et al. · British Journal Of Nutrition · 2021
DOI 10.1017/s0007114521002609
narrative_reviewCited 99×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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