AggieLAX said:
Tex117 said:
This is what the current science actually supports.
This is the most recent, I believe:
Link
Comparison of two nutritional protocols in body re-composition of resistance-trained participants.
Vargas-Molina S, Garca-Palumbo A, Garca-Sillero M, Bonilla DA, Petro JL, Aragon AA, Schoenfeld BJ, Bentez-Porres J.
Eur J Appl Physiol. 2026 Apr 6. doi: 10.1007/s00421-026-06209-6. Epub ahead of print.
PMID: 41940947.
"Trained" lifters (1.5+ years experience) for 10 weeks.
Take that as you will.
From claude
Barakat, C., Pearson, J., Escalante, G., Campbell, B., & De Souza, E. O. (2020). "Body Recomposition: Can Trained Individuals Build Muscle and Lose Fat at the Same Time?" Strength & Conditioning Journal, 42(5), 721. This is the systematic review underpinning most of what I said. It concluded that recomposition is most robustly demonstrated in previously untrained individuals, and it's the standard citation for the point that novices, returnees, and higher-body-fat individuals are where the effect is real. It also notes that consistently low-calorie dieting produces a hormonal environment not well suited to building musclewhich is the mechanism behind my claim about trained, lean lifters.
The frequently-cited RCT
Longland, T. M., Oikawa, S. Y., Mitchell, C. J., Devries, M. C., & Phillips, S. M. (2016). "Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial." American Journal of Clinical Nutrition, 103(3), 738746. DOI: 10.3945/ajcn.115.119339.
This is the study people cite to prove muscle gain in a deficit, so read it carefully. Forty overweight young men ran a 40 percent calorie deficit for four weeks while lifting and sprinting six days a week; the high-protein group (2.4 g/kg/day) gained 1.2 kg of lean mass and lost 4.8 kg of fat, while the lower-protein group (1.2 g/kg/day) held its lean mass and lost 3.5 kg.
The caveat that matters: the subjects were overweight and undergoing hard training, described by the senior investigator as "a gruelling affair". That is precisely the untrained-plus-higher-body-fat population where recomp works. It does not demonstrate that a lean, experienced lifter can do the same. It's often misread as a general proof; it isn't. It also ran only four weeks, and the authors acknowledged the diets differed in fat content too, so protein can't be cleanly isolated as the sole cause.
Protein intake range
The 1.62.2 g/kg figure traces to Morton et al. (2018), a meta-analysis in British Journal of Sports Medicine (52(6), 376384), which found resistance-training protein benefits plateauing around 1.6 g/kg. The higher end in a deficit is supported by Helms et al. (2014), "Evidence-based recommendations for natural bodybuilding contest preparation," Journal of the International Society of Sports Nutrition, 11:20. I cited these from memory rather than re-pulling them, so verify before relying on the exact numbers.
One honest note on source quality: the Barakat review is a narrative/systematic review, not a meta-analysis, and much of the trained-individual recomposition evidence within it comes from studies with methodological limits (DXA measurement error, short durations, no true untrained-lean-versus-trained-lean comparison). The direction of the evidence is solid; the precision is not. The literature genuinely does not contain a clean RCT showing appreciable hypertrophy in lean, advanced lifters in a deficitwhich is itself informative.