Role of protein and amino acids in promoting lean mass accretion with resistance exercise and attenuating lean mass loss during energy deficit in humans.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing literature on protein intake, resistance training, and energy balance without systematic review methodology.
PubMed 23645387 · doi:10.1007/s00726-013-1506-0
What was done
Narrative review summarizing evidence on the role of amino acids and dietary protein intake in regulating skeletal muscle turnover during resistance exercise, energy restriction, and energy overfeeding in humans.
What was found
Protein ingestion stimulates muscle protein synthesis and suppresses breakdown. Supplementation augments resistance training-induced gains in muscle mass and strength even in individuals habitually consuming adequate baseline protein (>0.8 g/kg/day) and attenuates lean mass loss during energy restriction. Overfeeding with moderate-to-high protein (15-25% energy or 1.8-3.0 g/kg/day) is associated with lean rather than fat mass accretion compared to low protein (5% energy or ~0.68 g/kg/day). No specific pooled effect sizes or statistical test values are reported in the abstract.
Why it matters
This review highlights that standard protein recommendations may be inadequate to maximize muscle accretion from resistance training or prevent muscle loss during caloric deficits.
Limits
As a narrative review, it lacks a systematic search protocol, formal quality appraisal, and meta-analytic quantification. The abstract does not specify participant characteristics (such as age, sex, and training status), sample sizes, or study durations.
Cited by
- supports Caloric deficits act as a catabolic stimulus on skeletal muscle.