Nutrition · 5 min read · Updated September 2026
How much protein do you need to build muscle?
The evidence-based protein range for building muscle, cutting and maintaining, how to split it across meals, and the myths about upper limits.
Key takeaways
- 1.6 g/kg/day captures most of the benefit; up to 2.2 g/kg for the last bit.
- In a deficit, lean lifters benefit from 2.3–3.1 g/kg of lean mass.
- Spread it across 3–5 meals of ~0.4 g/kg each.
- Total daily intake matters far more than timing.
Protein is the one macronutrient where the evidence is strong enough to give a clear answer.
The number
A 2018 meta-analysis by Morton and colleagues pooled 49 trials and found the muscle-building benefit of protein plateaued at about 1.6 g per kg of bodyweight per day, with the upper confidence limit at 2.2 g/kg. For an 80 kg lifter that is 128–176 g a day.
MuscleFlare's protein calculator targets 1.8 g/kg by default — enough margin to cover individual variation without wasting calories that could fuel training.
During a cut
A calorie deficit raises protein needs, because the body is more willing to break down muscle for energy. Helms et al. (2014) recommend 2.3–3.1 g per kg of lean mass for lean, resistance-trained people in a deficit. The leaner you are and the bigger the deficit, the closer to the top of that range.
If you carry a lot of body fat
Per-kg-of-bodyweight targets overshoot when a large share of that weight is fat. Above about 25% body fat (men) or 32% (women), calculate from an adjusted weight — the calculator does this automatically.
Per meal
Muscle protein synthesis responds to each protein feeding. Schoenfeld & Aragon (2018) suggest about 0.4 g/kg per meal across at least four meals to maximise the daily total. For an 80 kg person: roughly 32 g, four times a day.
That does not mean protein above ~30–40 g in one meal is "wasted" — it is still digested and used. It means four moderate meals are a slightly better use of the same total than two large ones.
Common questions
Is it bad for my kidneys? In healthy people, intakes in these ranges have not been shown to harm kidney function. If you have kidney disease, follow your doctor.
Do I need shakes? No. They are simply convenient. Meat, fish, eggs, dairy, legumes, tofu and tempeh all count.
Does timing around training matter? A little. A protein-containing meal within a few hours either side of training is sensible, but the daily total dwarfs the effect of timing.
Once protein is set, build the rest of your intake with the macro calculator.
Apply it to your numbers
Daily protein and per-meal targets from the best current evidence.
Written for healthy adults, for education — not medical advice. If you have a medical condition, are pregnant or have a history of disordered eating, speak to a qualified professional before changing your diet. How we handle evidence: methodology.
Next guideHow many calories should you eat to build muscle?