Protein Requirements — How Much Is Actually Optimal
The RDA of 0.8 g/kg is a deficiency floor, not a target. Here's the evidence-based intake for fat loss, muscle gain, and longevity — by goal.
The RDA is a floor, not a target
The 0.8 g/kg/day Recommended Dietary Allowance was set to prevent overt deficiency (negative nitrogen balance) in 97.5% of sedentary adults. It was never a recommendation for optimal body composition, performance, or longevity.
Evidence-based intakes by goal
| Goal | g/kg/day | Source |
|---|---|---|
| Avoid deficiency (sedentary) | 0.8 | RDA |
| General fitness / recovery | 1.2–1.6 | ACSM, AND, DC joint statement |
| Hypertrophy (muscle gain) | 1.6–2.2 | Morton et al. meta-analysis, 2018 |
| Fat loss while training (preserve muscle) | 2.0–2.4 | Helms et al., 2014 |
| Older adults (sarcopenia prevention) | 1.2–1.5 | Bauer et al., PROT-AGE 2013 |
| Endurance athlete | 1.2–1.6 | ACSM |
| Strength/power athlete (peak) | 1.7–2.2 | ISSN position stand |
Above ~2.2 g/kg, additional protein offers no demonstrated benefit for muscle growth in trained individuals, according to Morton’s 2018 meta-analysis of 49 studies.
Per-meal distribution
Muscle protein synthesis appears to saturate at roughly 0.4 g/kg per meal for trained individuals (~30–40 g for most people). Spreading total intake across 3–5 meals beats two big meals for 24-hour muscle protein balance.
”But what about my kidneys?”
In people with healthy kidneys, intakes up to 2.5–3.0 g/kg/day have been studied in controlled trials with no adverse renal effects (Devries et al., 2018; Antonio et al., 2016). The renal-damage claim originates from studies in people with pre-existing chronic kidney disease, for whom protein restriction is genuinely recommended.
Plant vs animal protein
Animal proteins (meat, dairy, eggs) are higher in leucine — the key amino acid that triggers muscle protein synthesis — and have more complete amino-acid profiles. Plant proteins can match the anabolic response if total intake is increased by ~15–20% and sources are varied (legumes + grains; or soy/pea isolates which are nearly complete).
Try it
Set your daily target with the protein calculator.
Sources
- Jäger R, et al. ISSN Position Stand: protein and exercise. JISSN. 2017;14:20.
- Morton RW, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training–induced gains in muscle mass and strength. Br J Sports Med. 2018;52:376–84.
- Helms ER, et al. A systematic review of dietary protein during caloric restriction in resistance trained lean athletes. Int J Sport Nutr Exerc Metab. 2014;24:127–38.
- Bauer J, et al. Evidence-based recommendations for optimal dietary protein intake in older people: the PROT-AGE study group. JAMDA. 2013;14:542–59.
- Antonio J, et al. A high protein diet has no harmful effects: a one-year crossover study. J Nutr Metab. 2016.