How much protein should I eat per day?
Reviewed and updated · Methodology
The U.S. Recommended Dietary Allowance (RDA) of 0.8 g/kg is the minimum to prevent deficiency in sedentary healthy adults — not an optimum for athletes, older adults, or people in a calorie deficit.
The International Society of Sports Nutrition (ISSN) position stand recommends 1.4–2.0 g/kg/day for most exercising adults. A 2018 meta-analysis by Morton et al. found muscle-protein gains from supplemental protein plateau at about 1.6 g/kg/day.
Older adults (65+) typically benefit from 1.0–1.2 g/kg/day to offset age-related muscle loss (sarcopenia). Pregnant and breastfeeding women have higher needs (~1.1 g/kg/day).
Spread intake across 3–5 meals of roughly 0.25–0.4 g/kg each to maximize muscle-protein synthesis, rather than loading most protein into one meal.
Is more than 2 g/kg/day harmful?
For healthy adults with normal kidney function, intakes up to ~2.2 g/kg/day are well tolerated in the literature. People with pre-existing kidney disease should follow their physician's recommendation.
Does the number change if I am losing weight?
Yes. In a calorie deficit, higher protein (1.6–2.4 g/kg) helps preserve lean mass while you lose fat. Evidence is strongest for resistance-training dieters.
- NASEM Dietary Reference Intakes — Protein — Institute of Medicine DRI for protein (RDA 0.8 g/kg, AMDR 10–35%)
- ISSN Position Stand: Protein and Exercise — Peer-reviewed consensus: 1.4–2.0 g/kg for active adults
- Morton et al., 2018 — Meta-analysis of protein supplementation & RET — Br J Sports Med: benefits plateau around 1.6 g/kg/day
- NIH Office of Dietary Supplements — Dietary Supplements for Weight Loss — Federal guidance on protein, supplements, and weight management
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