Effects of High-Protein Diets on Renal Function and Body Composition in Adults Without Chronic Kidney Disease: A Systematic Review and Meta-Analysis of Randomised Trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 42289790 · doi:10.1111/dom.70996
What was done
A systematic review and random-effects meta-analysis (searching PubMed, Embase, and Cochrane CENTRAL to May 2026) evaluating randomized controlled trials of high-protein diets (25%-35% of energy intake or ≥2.0 g/kg/day) versus normal- or low-protein diets in adults without chronic kidney disease. Primary outcomes were estimated glomerular filtration rate (eGFR) and serum creatinine; secondary outcomes were body fat percentage, total fat mass, and fat-free mass. Risk of bias was evaluated via Cochrane RoB 2 and certainty via GRADE.
What was found
Across 22 included trials, high-protein diets increased eGFR relative to controls (SMD 0.39, 95% CI 0.09 to 0.69; I² = 74.9%). Serum creatinine showed no significant change across 19 trials (n = 1044; SMD 0.08, 95% CI -0.09 to 0.25; I² = 20.8%). High-protein diets significantly reduced body fat percentage and total fat mass, but did not significantly change fat-free mass (numeric effect sizes for body composition outcomes were not reported in the abstract).
Why it matters
These findings suggest that high-protein intake promotes fat loss without inducing overt biochemical kidney damage in healthy adults, with observed eGFR increases likely reflecting benign, short-term hemodynamic adaptations (hyperfiltration).
Limits
Most trials had relatively short follow-up durations, leaving long-term renal outcomes uncertain. Kidney function was largely measured using creatinine-based estimates rather than direct GFR clearance metrics, and significant heterogeneity was present for the eGFR outcome (I² = 74.9%). Total participant count across all 22 trials was not reported in the abstract.
Cited by
- context Consuming extremely high amounts of protein can cause kidney damage.