Deficitly
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How much protein do you need to build muscle?
About 1.6 g of protein per kg of body weight a day (0.7 g per lb) gets most people the full muscle-building benefit of lifting; going up to 2.2 g/kg (1 g per lb) covers almost everyone. That's the finding of the largest meta-analysis on the question (Morton 2018). For a man of 90 kg (198 lb) building muscle the calculator suggests about 145 g a day, or 35 g at each of 4 meals. Protein only works with training: lifting is what tells your body to build.
Protein to build muscle by weight
| Weight | 1.6 g/kg | 2.2 g/kg | Per meal (×4) |
|---|---|---|---|
| 55 kg 121 lb | 90 g | 120 g | 20 g |
| 65 kg 143 lb | 105 g | 145 g | 25 g |
| 75 kg 165 lb | 120 g | 165 g | 30 g |
| 85 kg 187 lb | 135 g | 185 g | 35 g |
| 95 kg 209 lb | 150 g | 210 g | 40 g |
What the research says
Morton and colleagues pooled 49 trials with 1,863 people who lifted weights. Extra protein helped muscle gain up to about 1.6 g/kg a day; above that, gains levelled off, with the upper end of the estimate at about 2.2 g/kg. The International Society of Sports Nutrition recommends 1.4–2.0 g/kg for most people who exercise. Higher intakes aren't harmful for healthy people, just rarely needed, except during a hard diet: lean lifters cutting calories may benefit from 2.3–3.1 g per kg of lean mass.
Do women need less protein to build muscle?
Per kg, no: the same 1.6–2.2 g/kg applies. Women usually weigh less, so the grams are lower. Women tend to gain muscle more slowly in absolute terms, but respond to training just as well relative to their size (calories for women).
Spread it over the day
Four or more servings of about 0.4 g/kg each (25–40 g for most people) work better than one huge meal and a protein-free rest of the day. A serving within a few hours of training is useful, but the "30-minute anabolic window" matters far less than the daily total. More in how much protein per meal.
Calories matter too
Muscle needs building material and energy. A small surplus (about 0.25–0.5% of body weight a week) builds muscle with little fat; at maintenance, beginners and returning lifters can still gain (body recomposition). See how many calories to build muscle, and split the calories into protein, carbs and fat with the macro calculator.
Do you need protein shakes?
No, but they're convenient. A scoop of whey or plant protein usually has 20–25 g (check the label). Food works just as well: 100 g of chicken breast has 31 g, a pot of Greek yogurt 17 g. Whole-food options, ranked: foods highest in protein.
Sources
- Morton RW, Murphy KT, McKellar SR, 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 in healthy adults. Br J Sports Med 2018;52(6):376–384.
- Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr 2017;14:20.
- Schoenfeld BJ, Aragon AA. How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. J Int Soc Sports Nutr 2018;15:10.
- Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. J Int Soc Sports Nutr 2014;11:20.
- U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, SR Legacy (2018). Food IDs in the table notes.