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Strong evidenceTraining variable

Daily protein intake

For people who lift, total daily protein matters: eating about 1.6 g per kg of body weight per day maximizes muscle gains for most, and more brings little extra. During a diet, especially when lean, needs are higher. Food or supplements both count; the total is what matters.

What the science says

  • More protein adds muscle gains during training Strong evidence

    Morton et al.'s 2018 meta-analysis of 49 trials (1,863 people) found protein supplementation increased gains in strength and fat-free mass during resistance training. Nunes et al.'s 2022 meta-analysis of 74 randomized trials confirmed small additional gains in lean mass and lower-body strength.

  • Benefits level off around 1.6 g/kg per day Moderate evidence

    Morton et al. found no further fat-free mass gains above a total intake of about 1.62 g/kg/day; the upper end of the confidence interval was about 2.2 g/kg. Nunes et al. found the lean-mass benefit in adults under 65 at intakes of 1.6 g/kg/day or more.

  • Dieting lifters need more Limited evidence

    Helms et al.'s 2014 systematic review of 6 studies in lean, resistance-trained athletes in a calorie deficit suggested 2.3–3.1 g per kg of fat-free mass, higher the leaner the athlete and the larger the deficit.

  • Effect is dose-dependent in the general population Moderate evidence

    Tagawa et al.'s 2020 meta-analysis of 105 articles found each extra 0.1 g/kg/day of protein was linked to more lean body mass, with larger gains below about 1.3 g/kg/day than above it.

How to apply it

Hit a daily total first, then split it across your meals.

Building muscleAbout 1.6 g/kg body weight/day (up to 2.2 g/kg)
Calorie deficit, lean lifterAbout 2.3–3.1 g/kg of fat-free mass/day
Meals3–5 meals of about 0.3–0.4 g/kg each
Example, 80 kg personAbout 130 g/day for building muscle
SupplementsOnly to reach the total if food falls short

Who should be careful

High protein intakes are well tolerated by healthy adults. People with kidney disease or other medical conditions should set their intake with a physician or dietitian.

Frequently asked questions

How much protein do I need to build muscle?

About 1.6 g per kg of body weight per day. A meta-analysis of 49 trials found no further fat-free mass gains above about 1.62 g/kg/day.

Do I need more protein when cutting?

Probably. A review of lean, resistance-trained athletes in a calorie deficit suggested 2.3–3.1 g per kg of fat-free mass, higher when leaner or dieting harder.

Do I need protein shakes?

No. The studies count total daily protein; shakes only help if food does not get you to your target.

Scientific references

More training variables