Body Metrics Calc

Protein calculator for muscle gain

To build muscle, eat at least 1.6 g of protein per kg of body weight a day (0.73 g per lb), up to 2.2 g/kg (1 g per lb).

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Estimates, not medical advice.

To build muscle, the research points to at least 1.6 grams of protein per kilogram of body weight a day, which is 0.73 grams per pound. Some people may benefit from up to 2.2 g/kg, about 1 gram per pound. That is two to almost three times the 0.8 g/kg RDA set for sedentary adults.

Enter your weight in pounds or kilograms. The calculator shows your daily range in grams, the RDA for comparison, and an even split over four meals.

Where the numbers come from

1.6 g/kg, the minimum effective intake. Morton and colleagues (2018, British Journal of Sports Medicine) pooled randomised trials of protein supplements in adults doing resistance training. Gains in fat-free mass levelled off at about 1.6 g/kg a day. Eating more than that did not add measurable muscle on average.

2.2 g/kg, the upper end. The same analysis put the upper 95% confidence limit of that plateau at 2.2 g/kg. People who respond best to protein may need up to that much, so the authors suggest it as a reasonable ceiling for anyone trying to maximise gains.

0.8 g/kg, the RDA. The Institute of Medicine's Dietary Reference Intakes (2005) set the adult protein RDA at 0.8 g/kg a day. It is meant to cover the needs of nearly all healthy adults. It was not set for people trying to add muscle.

The International Society of Sports Nutrition's position stand (Jäger et al. 2017) gives a wider band for exercising people: 1.4 to 2.0 g/kg a day. The calculator uses the Morton range because it was measured on muscle gain specifically.

The formula in plain words

Multiply your weight in kilograms by each figure. For pounds, multiply by 0.4536 first.

RDA: 0.8 x kg. Minimum for muscle gain: 1.6 x kg. Upper end: 2.2 x kg. Per meal: 0.4 x kg.

Worked example

A person weighs 70 kg (154 lb).

RDA: 0.8 x 70 = 56 g a day.

Muscle gain: 1.6 x 70 = 112 g, up to 2.2 x 70 = 154 g a day.

Per meal: 0.4 x 70 = 28 g, four times a day, which adds up to 112 g.

Starting from pounds gives the same answer: 154 x 0.4536 = 69.9 kg, and 1.6 x 69.9 = 112 g.

Spreading it over the day

Schoenfeld and Aragon (2018, Journal of the International Society of Sports Nutrition) reviewed how much protein a single meal can usefully supply for muscle building. They suggest about 0.4 g/kg per meal across at least four meals to reach the 1.6 g/kg minimum. The calculator shows that per-meal figure.

Who it does not suit

The studies behind these numbers were run on healthy adults doing resistance training. They do not apply to children or teenagers, or during pregnancy. People with kidney disease, reduced kidney function or another condition that limits protein should follow their doctor's advice instead.

Body weight is a blunt input. For someone carrying a lot of body fat, a range based on total weight runs high. Some people use a goal weight or their lean body mass instead, but the studies above used total body weight, so that is what the calculator uses.

Protein alone does not build muscle. The 1.6 g/kg plateau was measured in people on a resistance training program. Track your progress with the one-rep max calculator or a tape and the body fat calculator.

Sources

  1. pubmed.ncbi.nlm.nih.gov: Morton et al. 2018 (Br J Sports Med)
  2. pubmed.ncbi.nlm.nih.gov: Jäger et al. 2017, ISSN position stand
  3. pubmed.ncbi.nlm.nih.gov: Schoenfeld & Aragon 2018 (JISSN)
  4. nap.nationalacademies.org: IOM Dietary Reference Intakes (2005)

Questions people ask

How much protein do I need to build muscle?

At least 1.6 g per kilogram of body weight a day, up to about 2.2 g/kg. In pounds that is 0.73 to 1 g per pound. A 70 kg (154 lb) person needs 112 to 154 g a day. These figures come from a 2018 meta-analysis by Morton and colleagues of resistance training studies.

Is 1 gram of protein per pound too much?

No, it is the top of the range. One gram per pound is about 2.2 g/kg, the upper 95% confidence limit in Morton et al. 2018. Going above it was not shown to add more muscle. Most people see their gains level off near 1.6 g/kg (0.73 g per lb).

What is the protein RDA?

0.8 g per kilogram of body weight a day for healthy adults, from the Institute of Medicine's Dietary Reference Intakes. It covers basic needs for nearly everyone. It was not set for people who are training to add muscle, which is why the muscle gain range is higher.

How much protein should I eat per meal?

About 0.4 g per kilogram of body weight per meal, across at least four meals. That is 28 g a meal at 70 kg. The figure comes from Schoenfeld and Aragon (2018), and four meals at that size add up to the 1.6 g/kg minimum.

Should I use my current weight or my goal weight?

The studies used total body weight, so the calculator does too. If you carry a lot of body fat, the result runs high, and some people use a goal weight or lean body mass instead. That is a judgement call, not a published rule.

What does the ISSN recommend?

The International Society of Sports Nutrition's 2017 position stand says 1.4 to 2.0 g/kg a day is enough for most exercising people to build and maintain muscle. That band overlaps the 1.6 to 2.2 g/kg range used here.

Is a high protein diet safe for my kidneys?

These ranges are for healthy adults. If you have kidney disease or reduced kidney function, talk to your doctor before you raise your protein intake. The same applies to any condition where you have been told to limit protein. This page cannot assess your health.