Building muscle in a calorie deficit

// What the research shows

Murphy & Koehler (2022) used a meta-analysisMeta-analysis A study of studies: the results of many individual studies are pooled statistically. More in the glossary → and meta-regressionMeta-regression A method within a meta-analysis that tests whether the size of an effect depends on a characteristic of the studies. More in the glossary → to compare resistance training with and without an energy deficitCalorie deficit You take in less energy than you use. The body draws on its reserves. More in the glossary →. Lean mass gains were clearly impaired in a deficit, while strength gains were comparable. The larger the deficit, the worse the lean mass outcome. At about 500 kcal/day, the average was neither gain nor loss.

// In practice

• If building muscle is your main goal: avoid long dieting phases.
• If you want to lose fat and keep muscle: keep the deficit moderate (ideally below 500 kcal/day), keep training hard, eat plenty of protein.
• You can often keep getting stronger during a diet, especially as a beginner.

// Limitations & open questions

Many included studies involved older or untrained participants. Data for experienced lifters are thinner.

// Sources

• Meta-Analyse 2022Murphy & Koehler – Energy deficiency impairs resistance training gains in lean mass but not strength (Scand J Med Sci Sports) ↗

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