Keto did not blunt lifters' one-rep max strength

Ketogenic diets keep finding new audiences, and lifters are one of them, drawn by claims about body composition. The obvious worry is strength: carbohydrate is the fuel most associated with hard resistance training, so cutting it drastically raises the question of whether maximal performance suffers. Individual trials have been small and pointed in different directions, which is exactly the situation a pooled analysis exists to resolve. This review set out to test whether a ketogenic diet, run alongside resistance training, changes strength in people who already train.

The authors ran a systematic review and meta-analysis, searching PubMed, Scopus and Web of Science for trials that combined a ketogenic diet with resistance training in trained participants. They then pooled the results into two separate meta-analyses of maximal strength. One covered the one-rep max squat, drawing on 106 trained participants or athletes. The other covered the one-rep max bench press, evaluating 119 participants. In each case the ketogenic groups were compared against non-ketogenic controls on the change in maximal strength.

There were no significant differences between ketogenic and control groups on either lift. Neither the squat nor the bench press one-rep max was measurably impaired by the diet, and the effect size was actually slightly higher in the ketogenic group, though not enough to reach significance. The authors' conclusion is careful on both fronts: ketogenic diets do not appear to hurt one-rep max performance, but they also note that this test may not be the best tool for judging performance across a hypertrophy-based strength session, where more repeated work is done.

This pushes back on the common assumption that very low-carbohydrate eating and heavy lifting are incompatible, at least where a single maximal effort is concerned. It sits alongside a broader, unsettled debate about ketogenic diets and body composition in trained people, which this analysis was framed around but does not resolve here. The big open question is repeated-effort performance: a one-rep max is one all-out lift, and the authors themselves flag that longer, higher-volume sessions may respond differently. Larger trials measuring session-level performance would close that gap.

If you train seriously and have been curious about a ketogenic diet, this is a reason to think your top-end strength on a single maximal lift is unlikely to collapse. It is not evidence that the diet helps strength, and it says little about how you would feel or perform across a long, repetition-heavy session, which the authors explicitly note their measure cannot capture. The pooled numbers are also modest, at just over a hundred lifters per lift. Treat this as one reassuring data point on max strength, not a verdict on keto for training overall.