How much protein should I eat a day, by goal and bodyweight

What people ask us next.

Q01

How much protein should I eat a day to build muscle?

1.6 g/kg/day is the evidence-backed target for maximizing resistance-training gains, per Morton et al. 2018 (meta-analysis of 49 studies, n=1,863). For an 80 kg lifter that is 128 g/day; for a 68 kg lifter, ~109 g/day. Going above ~2.2 g/kg shows no added lean-mass benefit. Total still matters less than people think relative to training stimulus, but 1.6 g/kg is the number to hit.

Q02

Is 0.8 g/kg the right protein target?

Only if you are sedentary and your goal is to avoid deficiency. 0.8 g/kg/day is the RDA (IOM 2005), defined as the minimum that prevents nitrogen-balance loss in 97.5% of healthy sedentary adults. It is a floor, not an optimum. Anyone who trains, is over 65, is dieting, or is pregnant needs more: 1.6 g/kg for lifters, 1.0-1.2 for older adults, 1.8-2.4 while cutting.

Q03

How many grams of protein per day for a woman?

By the same per-kilogram math: a sedentary 68 kg woman needs ~54 g/day (RDA), an active one ~82-109 g (1.2-1.6 g/kg), and ~122-163 g while dieting (1.8-2.4 g/kg). Requirements scale with bodyweight and activity, not sex, so a woman and a man of the same weight and training status target the same number. Pregnancy adds ~25 g/day in the second and third trimesters.

Q04

Can you eat too much protein in a day?

For healthy people, no practical harm has been shown. Devries et al. 2018 found no effect of high protein on kidney function (eGFR) in adults with healthy kidneys, and trials up to ~3.3 g/kg/day in resistance trainers (Antonio 2016) found no adverse changes. The real ceiling is functional: above ~2.2 g/kg there is no added lean-mass benefit, so extra protein is just expensive calories. Pre-existing kidney disease is the one exception and is a clinician question.

Q05

Does protein need to be spread across the day?

It helps. Maximal muscle protein synthesis per meal needs ~0.4 g/kg (~2.5-3 g leucine), per Moore et al. 2015. Eating 3-4 meals each clearing that threshold produces a higher daily anabolic response than loading most protein into one meal. For an 80 kg person, aim for ~32 g per meal across 3-4 meals rather than 100 g at dinner.

Q06

Should I count protein in grams or as a percentage of calories?

Grams per kilogram of bodyweight, not percent of calories. A percent target moves with your total intake, so the same 30% can be far too little while bulking or far too much while cutting. The literature (Morton, Helms, Bauer) is written in g/kg precisely because the muscle requirement is tied to body mass, not to calorie intake. Set grams first, then let carbs and fat fill the rest.

Q07

What is the easiest way to hit my daily protein number?

Pick a per-meal anchor and repeat it. For most active adults, ~30-40 g per meal across 3-4 meals hits 1.6 g/kg without tracking every gram: roughly 150 g cooked chicken, 300 g Greek yogurt, or a scoop of whey plus eggs each clear ~30 g. Run your exact target and meal split through the Macro Calculator, which also outputs the cheapest sources by cost per gram.