The magnitude and progress of lean body mass, fat-free mass, and skeletal muscle mass loss following bariatric surgery: A systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review of longitudinal observational studies tracking body composition changes
PubMed 34664391 · doi:10.1111/obr.13370
What was done
A systematic review and random-effects meta-analysis of 59 studies (evaluating 37 cohorts for lean body mass [LBM], 20 for fat-free mass [FFM], and 3 for skeletal muscle mass [SMM]) identified via PubMed, Embase, and Web of Science. Preoperative and postoperative body composition changes were evaluated at multiple time points up to 12 months.
What was found
At 12 months after bariatric surgery, pooled losses were: - LBM: -8.13 kg (95% CI -9.01 to -7.26) - FFM: -8.23 kg (95% CI -10.74 to -5.73) - SMM: -3.18 kg (95% CI -5.64 to -0.71) Roughly 55% of 12-month LBM loss occurred within 3 months post-surgery, followed by a slower rate of loss up to 12 months. FFM and SMM exhibited similar patterns.
Why it matters
Lean tissue loss after bariatric surgery is front-loaded in the first 3 months, highlighting a critical perioperative window for targeted nutritional and exercise interventions.
Limits
Total participant n is not reported in the abstract. Only 3 studies directly measured skeletal muscle mass (SMM) versus broader lean mass metrics. Postoperative outcomes beyond 12 months and differences across specific surgical procedures are not described in the abstract.
Cited by
- supports Rapid weight loss from GLP-1 medications and bariatric surgery leads to substantial loss of skeletal muscle mass.