Compound or practice · Nutrition
Protein intake
The macro with the strongest evidence in all of nutrition — most people building muscle need 1.6–2.2 g/kg, full stop.
- Overall grade
- Grade A
- Last revised
- 4
- graded outcomes
- 3
- references listed
A hand-written entry in Prometheus's bundled library. Its grades are the entry's own reading of the evidence, not a peer-reviewed review.
3 at grade A · 3 at grade B · 1 at grade C · 1 at grade D — 8 graded rows
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Lean mass (with resistance training)Evidence grade A
Plateau ~1.6 g/kg/day; meta-regression of 49 RCTs
Moderatehigh
- Strength gainsEvidence grade A
Mediated through lean mass
Smallhigh
- Satiety / fat-loss adherenceEvidence grade B
Highest-satiety macro per calorie
Moderatehigh
- Kidney harm (healthy adults)Evidence grade D
No harm signal in healthy kidneys — persistent myth
Trivialhigh
Conditions
How the entry reads its effect on diagnosed conditions: the direction first, then the grade. Never a substitute for the person who treats you.
- Sarcopenia (age-related muscle loss) ImprovesEvidence grade A1.2–1.6 g/kg plus resistance work is the standard of careGrade A
- Obesity / weight management ImprovesEvidence grade BHighest-satiety macro; protects lean mass in a deficitGrade B
- Osteoporosis May improveEvidence grade BHigher intakes associate with better bone density — the old myth ran backwardsGrade B
- Advanced kidney disease May worsenEvidence grade CRestriction only under nephrology care; healthy kidneys are unaffectedGrade C
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
- Thin evidence: Kidney harm (healthy adults) (grade D).
Up: % of max response. Across: g/kg/day. Meta-regression plateau at ~1.6 g/kg — the range above it is insurance for cuts and heavy blocks.
The evidence in words
The number that matters
Meta-regression puts the muscle-growth plateau at ~1.6 g/kg/day, with 2.2 g/kg as insurance during a deficit or high training loads. Below 1.2 g/kg while training hard, you're leaving measurable lean mass on the table.
Distribution and timing
Per-meal 'limits' are mostly myth — total daily intake dominates. Spreading over 3–4 feedings of ≥0.4 g/kg is a modest optimization; the anabolic window is hours wide, not minutes. Whey is convenience, not magic: food-first works identically at equal totals.
Practical math
80kg lifter → 130–175g/day. That's roughly: 3 palm-sized meat/fish servings + greek yogurt + 1 scoop whey. If your log shows a 40g gap, one scoop closes it — that's the whole trick.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Building
- 1.6–2.2 g/kg/day, 3–4 feedings, ≥0.4 g/kg each.
- Cutting
- Hold the high end (2.0–2.2 g/kg) — protein is what protects muscle in a deficit.
Goes with
- CreatineThe two supplements with A-grade lean-mass evidence — additive, not redundantEvidence grade A
Questions people ask
Plant protein worse?
Slightly lower leucine per gram — fixable by eating ~10–20% more total or mixing sources. At equal leucine, growth is equal.
Only absorb 30g per meal?
You absorb essentially all of it; the 'limit' refers to acute synthesis rates, and slower digestion smooths that out anyway. Daily total wins.
Related reading
Entries that share this one's tags or conditions.
- Casein ProteinThe slow-release milk protein — a small overnight-recovery edge, mostly a convenience choice.Evidence grade B
- Casein Protein for Overnight muscle synthesisEvidence grade B — Pre-sleep dosingEvidence grade B
- Casein Protein: side effects, safety & interactionsVery safe; contains lactose.Evidence grade B
- Egg ProteinA high-quality dairy-free animal protein — solid, unremarkable, more expensive than whey.Evidence grade B
Sources
As this entry records them: title, journal and year. None carries a DOI or PubMed id, so none is linked as a verified paper. Each link searches PubMed for the title; check that what you find is what the entry describes.
- 1.Protein supplementation and resistance-training adaptations: meta-regression — Br J Sports Med, 2018. Search PubMed (opens in a new tab)
- 2.Per-meal protein distribution and anabolism — J Int Soc Sports Nutr, 2018. Search PubMed (opens in a new tab)
- 3.Dietary protein and kidney function in healthy adults: meta-analysis — J Nutr, 2018. Search PubMed (opens in a new tab)
Last revised . A grade is this entry's reading of the evidence, not medical advice.