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

1. 01

   Sedentary adult (no training): 0.8 g/kg/day, the RDA floor

   0.8 g/kg/day is the RDA (IOM 2005): ~58 g for a 73 kg adult. This is the amount that prevents nitrogen-balance deficiency in 97.5% of healthy sedentary people, set as a minimum, not an optimum. Even without training, the protein-quality and satiety literature suggests ~1.0-1.2 g/kg is a better practical target; 0.8 is the line below which you risk loss, not the line you aim for.

2. 02

   General fitness / recreational lifter: 1.2-1.6 g/kg/day

   For someone training 2-4x/week and not chasing maximal hypertrophy, 1.2-1.6 g/kg/day covers recovery and lean-mass maintenance. For a 75 kg person that is 90-120 g/day. The lower end suits maintenance; move toward 1.6 g/kg if actively building. This range is where most active general-population adults land.

3. 03

   Resistance training for muscle gain: 1.6 g/kg/day

   1.6 g/kg/day is the meta-analytic plateau for maximizing resistance-training gains in lean mass (Morton et al. 2018, n=1,863). For an 80 kg lifter, 128 g/day; for a 68 kg lifter, ~109 g/day. The confidence interval extends to ~2.2 g/kg, so up to that ceiling is reasonable insurance, but the central estimate where gains stop increasing is 1.6 g/kg. This is the number most lifters should anchor to.

4. 04

   Fat loss / calorie deficit: 1.8-2.4 g/kg/day (or g/kg of fat-free mass)

   In a deficit, higher protein protects muscle and increases satiety. Helms et al. 2014 recommend ~2.3-3.1 g/kg of fat-free mass for lean dieting athletes; for general dieters, ~1.8-2.4 g/kg of bodyweight is the practical translation. The thermic effect of protein (~25-30% of its calories burned in digestion vs ~5-10% for carbs) gives a modest metabolic edge while cutting. This is the one scenario where eating toward the top of the range is clearly justified.

5. 05

   Adults over 65: 1.0-1.2 g/kg/day to beat anabolic resistance

   Older adults have a blunted muscle-protein-synthesis response to the same protein dose (anabolic resistance). The PROT-AGE study group (Bauer et al. 2013) recommends 1.0-1.2 g/kg/day for healthy older adults and 1.2-1.5 g/kg for those who are ill or doing resistance exercise, well above the 0.8 RDA. Per-meal dose matters more here: ~0.4 g/kg per meal helps clear the higher leucine threshold aging muscle requires.

6. 06

   Pregnancy and lactation: ~1.1 g/kg/day

   The RDA rises to ~1.1 g/kg/day in pregnancy (an added ~25 g/day in the second and third trimesters) per the IOM, and similar in lactation. Some analyses (Stephens et al. 2015) argue requirements during late pregnancy may be higher still. This is general nutrition guidance; specific medical needs are a clinician question, not a calculator question.

7. 07

   How to split it: ~0.4 g/kg per meal, 3-4 meals

   Total protein is necessary but not sufficient. Maximal muscle protein synthesis per meal requires ~0.4 g/kg (Moore et al. 2015), roughly the ~2.5-3 g leucine threshold. For an 80 kg person that is ~32 g per meal across 3-4 meals. Front-loading all your protein into dinner wastes part of the dose; spreading it raises the daily anabolic response, the same principle the Macro Calculator splits for you.

8. 08

   The ceiling: ~2.2 g/kg/day, and the kidney non-issue

   There is no measured lean-mass benefit above ~2.2 g/kg/day (Morton 2018 upper CI). Higher intakes are not harmful in healthy people: Devries et al. 2018 (meta-analysis) found no effect of high protein on kidney function (eGFR) in adults with healthy kidneys. The protein-harms-kidneys claim applies to pre-existing chronic kidney disease, where intake should be set by a clinician. For everyone else, the ceiling is about diminishing returns and cost, not safety.

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.