How Much Protein Do You Need to Build Muscle?

For adults who lift weights, a large meta-analysis found that extra protein stopped adding muscle at about 1.6 grams per kilogram of body weight per day (0.73 g per pound). The upper end of its estimate was 2.2 g/kg, which is about 1 gram per pound. The RDA of 0.8 g/kg is a minimum for general health, not a muscle-building target. For an 80 kg (176 lb) person, 1.6 g/kg works out to about 128 to 130 g of protein a day.

The Numbers at a Glance

Source	g per kg	g per lb	What it is for
RDA (National Academy of Medicine)	0.8	0.36	Minimum to meet basic needs
Dietary Guidelines 2025–2030	1.2 to 1.6	0.54 to 0.73	General goal for adults, adjusted for calorie needs
Morton et al., 2018 meta-analysis	1.62 (range 1.03 to 2.20)	0.73 (0.47 to 1.0)	Where more protein stopped adding muscle with strength training
“1 gram per pound” gym rule	2.2	1.0	A round number at the top of the research range

What the Muscle Research Found

Morton and colleagues pooled 49 randomized trials with 1,863 people who did resistance training for at least six weeks. Adding protein increased gains in strength and in fat-free mass, though the average extra gain was modest: 0.30 kg of fat-free mass. When they plotted total daily protein against muscle gain, the benefit leveled off at 1.62 g/kg a day.

The 95% confidence interval for that break point ran from 1.03 to 2.20 g/kg. That is why 1.6 g/kg is often used as a target and 2.2 g/kg as an upper end for people who want some margin. The same analysis found that extra protein made less difference as age increased and more difference in people who already trained. The training itself does most of the work.

Is 1 Gram per Pound Too Much?

One gram per pound equals 2.2 g/kg, the top of that range. For most people it is more protein than the pooled trials show is needed for muscle. The extra protein uses calories that could go to carbohydrates, which fuel training, or to fruit, vegetables and whole grains.

Many of the trials had people eating enough to maintain or gain weight. Protein needs during a calorie deficit were not the focus of this analysis, and some people who want to keep muscle while losing weight choose the upper part of the range.

How to Spread It Across the Day

A review by Schoenfeld and Aragon suggests about 0.4 g/kg per meal across at least four meals to reach 1.6 g/kg a day, and up to 0.55 g/kg per meal for people aiming at 2.2 g/kg. Hitting the daily total is the main goal. Spreading it out is a practical way to get there.

Protein also takes more energy to digest than other nutrients. A review of diet-induced thermogenesis puts it at 20 to 30% of protein’s calories, compared with 5 to 10% for carbohydrate and 0 to 3% for fat (Westerterp, 2004). Over a whole day, that is a small effect.

Worked Example

Protein Targets for an 80 kg (176 lb) Lifter

Target	Arithmetic	Grams a day
RDA	80 × 0.8	64 g
Dietary Guidelines range	80 × 1.2 to 80 × 1.6	96 to 128 g
Morton break point	80 × 1.62	129.6 g (about 130 g)
Upper end (same as 1 g/lb)	80 × 2.2	176 g
Per meal, four meals	80 × 0.4 = 32 g × 4	128 g

A practical target for this lifter is about 130 g a day, or 32 to 33 g at each of four meals. Going up to 176 g adds 46 g of protein, which is 46 × 4 = 184 calories a day, that the pooled trials don’t show turning into more muscle.

How This Compares With Our Macro Planner

The Macro Planner sets protein at 30% of your calorie target. At 2,400 calories that is 2,400 × 0.30 ÷ 4 = 180 g, or 2.25 g/kg for an 80 kg person, a little above the top of the research range. That is fine if you like eating that way. If you would rather spend those calories on carbohydrates, set protein by body weight (about 1.6 g/kg) and fill the rest with carbs and fat.

Where the protein comes from also matters for long-term health. Diets with more plant protein and fish are associated with better outcomes than diets high in red meat (Harvard T.H. Chan School of Public Health).

Who Needs Different Advice

Kidney disease. Some people with chronic kidney disease need a moderate amount of protein so waste doesn’t build up in the blood, while too little can lead to malnutrition. The NIDDK advises working with a dietitian to find the right amount.
Diabetes, liver disease, pregnancy or breastfeeding. Protein needs and safe ranges can differ. Ask your doctor or a registered dietitian before raising intake a lot.
A history of eating disorders. Exact macro targets can feed restrictive habits. A clinician can help you decide whether tracking is a good idea at all.

What This Doesn’t Cover

This guide covers healthy adults who do resistance training. It doesn’t cover endurance athletes, children and teens, older adults with frailty or muscle loss, the quality or safety of protein supplements, or medical diets. The research above measured muscle and strength over weeks to months, not long-term health outcomes. This page is for education only and is not medical advice.

Plan Your Calories and Macros

Get a calorie target from your age, height, weight and activity, then compare its protein figure with the per-kilogram range above.

Open the Macro Planner

Sources: Morton et al., 2018, British Journal of Sports Medicine (1.62 g/kg break point, 1.03 to 2.20 interval); Schoenfeld and Aragon, 2018 (protein per meal); Dietary Guidelines for Americans, 2025–2030 (1.2 to 1.6 g/kg); Harvard Nutrition Source, Protein (0.8 g/kg RDA).