Almost every protein number you have been given answers a different question
The figure on the food label is a floor for avoiding a shortfall. The figure quoted by lifters is a plateau measured in people who were not dieting. The figure that matters to most people is the one measured in people eating less than they burn, and it is the one least often quoted. Here are nine measured intakes, each with the group of people it came from.
The Archive’s position
This is opinion, not a finding. Everything else on this page is the evidence.
Eat one gram of protein per pound of your goal bodyweight, every day, and treat it as the floor, not the target. If you want to weigh 200 pounds, you eat 200 grams, whether you weigh 175 or 260 right now.
Why we hold it
- The RDA, the official daily recommendation, is a floor against running short, not the best amount. It was worked out by counting protein in and out in inactive adults, and it answers one question: when do you stop losing protein from your body? Almost nobody reading this is trying to just not waste away.
- The authors of the paper most often used to argue against this recommended the number themselves. The 2018 review that found the 1.62 g/kg plateau says in its own discussion that, since its likely range reached 2.20, it may be wise to recommend about 2.2 g/kg a day for people trying to get the most muscle from training. That is one gram per pound, from the very source usually quoted against it.
- A second, separate method lands on the same top figure. Tracking a tagged protein building block in the breath, instead of counting protein in and out, put the top of the likely range at 2.2 g/kg a day in trained lifters. Two methods with nothing in common reaching the same ceiling is worth more than either one alone.
- Nearly everyone who cares about this is eating less to lose weight, and that changes the answer. In the two controlled studies that tested it directly, roughly 2.3 to 2.4 g/kg beat 1.0 to 1.2 g/kg on lean mass by a wide margin. In one of them, the higher protein group gained muscle while losing fat.
- Goal weight is a workable stand-in for lean mass. Sports nutrition research scales protein to lean mass, which nobody knows without a scan. Goal weight gets close to it, and it stops a person at 300 pounds from working out a target their muscle does not need.
- Being wrong costs more one way than the other. In healthy people with normal kidneys, four months at 2.6 to 3.3 g/kg changed no kidney, liver or cholesterol marker. Eating too little protein while cutting calories reliably costs lean tissue you then have to rebuild.
- It is a rule a person can actually follow. A number you can work out in your head and hit without a spreadsheet gets followed. A more precise number that needs a body scan does not.
Where this goes beyond the evidence
The central estimate is 1.6 g/kg, not 2.2, and no pooled review has ever found a plateau at 2.2. The 2.2 figure is the top of the likely range on a result that was not clear, which is a reason to doubt the ceiling, not proof of a higher one. The sharper problem is a study that tested this directly. 39 adults eating 40 percent less were given 0.8, 1.6 or 2.4 g/kg for three weeks. Both higher groups beat the RDA at protecting lean mass, but 1.6 and 2.4 could not be told apart. That is the closest thing to a head-to-head test of this rule, and it found no advantage to the higher number. The honest summary is that the gap between 1.6 and one gram per pound is roughly 40 to 60 grams a day, at an intake where no harm has been measured in healthy kidneys. Choosing the top of the range buys insurance against real uncertainty. It does not buy a measured extra effect, because in the one study built to find one, there was none to find.
Who this is not for
Anyone with reduced kidney function or chronic kidney disease. The review that cleared high protein for kidney function only included adults without kidney disease, and its authors limit the conclusion to them, so it does not carry over. The rule also breaks at the edges of its own math. Someone at 150 pounds aiming for 200 would be eating close to 3 g/kg of what they weigh now, past every measured plateau. Someone very heavy aiming far lower lands below the range the research on eating less recommends. It ignores height entirely. And 200 grams is 800 calories, which squeezes a smaller person's calorie cut hard. It is a good default, not a law of physics.
The arithmetic, worked
Take someone who weighs 230 pounds and wants to weigh 200. The rule says 200 grams of protein a day, not 230. In the units the research uses, 200 grams against a goal weight of 90.7 kg is 2.2 grams per kilogram (g/kg) of goal body weight.
Now put that against the advice for exactly this situation: an adult eating less than they burn, trying to hold on to lean mass. That research recommends 2.3 to 3.1 grams per kilogram of fat-free mass. If the person in the example carries 160 pounds of lean tissue, 200 grams works out at 2.75 g/kg of fat-free mass. That sits inside that range, not above it.
That is the case for the rule in one paragraph. It is not that one gram per pound is a magic number. It is that scaling to goal weight lands a person close to the published advice for their situation, using a number they can work out without a body scan.
What gets dropped when the 1.6 figure is quoted
The 2018 review in the British Journal of Sports Medicine is the most cited paper in this argument, and it is a good paper. It pooled 49 studies with 1,863 people. It reported that protein above 1.62 g/kg/day produced no further gain in fat-free mass during strength training. That sentence is usually where the quoting stops.
Two things in the paper rarely travel with it. First, the point where gains flatten out did not pass the usual test for being more than chance. The authors say so themselves in their results. Second, the likely range for that point runs from 1.03 to 2.20 g/kg/day. The same data fits a plateau near 1 gram per kilogram. It also fits one at 2.2, which is one gram per pound.
This does not make the figure wrong or the paper weak. It makes 1.62 a middle estimate with real doubt around it, not a hard ceiling. Anyone using it to say higher intakes are definitely pointless is claiming more precision than the analysis gave. A third gap matters just as much. Every study in it was done in people training while eating about enough to hold their weight. So it was never a test of what happens when you are dieting.
And then there is the sentence in the paper that almost never gets quoted at all. In the discussion, right after reporting the range, the authors write that since the range spanned 1.03 to 2.20, it may be wise to recommend around 2.2 g/kg/day for people trying to get the most fat-free mass out of strength training. The paper cited everywhere to argue that 1.6 is the ceiling recommends 2.2 in its own text. And 2.2 g/kg is one gram per pound.
A second line of evidence reaches the same number a completely different way. One method, called indicator amino acid oxidation, measures a labelled tracer in the breath instead of counting nitrogen in and out. In trained lifters it found an average need of 1.7 g/kg/day, with an upper limit of 2.2. Two methods that share no assumptions landing on the same ceiling is a stronger signal than either on its own.
The case against going that high is a single study, and it is the best one here. Thirty-nine adults eating 40% less than they burned were given 0.8, 1.6 or 2.4 g/kg for three weeks. Both higher groups protected fat-free mass better than the RDA. Between 1.6 and 2.4 there was nothing to separate them. If you want the strongest argument that one gram per pound is more than you need, that is it. It is on this page, not left out of it.
Nine measured intakes, and who they were measured in
- 0.83 g/kg/day0.38 g/lb
Measured in
235 individual adults across 19 nitrogen balance studies (which count the protein the body takes in against what it loses), pooled to set the current RDA, the official daily protein recommendation
The amount that covered 97.5 percent of people came out at 0.83 g/kg a day, and the typical person needed 0.66 g/kg a day. That is the number printed on food labels.
Review of studiesMeta-analysis of nitrogen balance studies for estimating protein requirements in healthy adults (2003)What this does not show
This is the intake at which an inactive adult stops losing protein from the body. It was never meant as the amount that builds or best protects muscle, and the authors did not present it as one. A floor is not a target.
- 1.62 g/kg/day0.73 g/lb
Measured in
1,863 people across 49 weight training trials, with the turning point itself worked out from 42 study groups and 723 people
The widely quoted plateau. Above roughly 1.6 g/kg a day, extra protein added no more lean mass during weight training.
Review of studiesA 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 (2018)What this does not show
Two things, and both are usually dropped when this number is quoted. First, the turning point was not a clear result, and the authors say so in the paper. Its likely range runs from 1.03 to 2.20 g/kg a day, so the same data fit a plateau near 1 g/kg just as well as one at 2.2. Second, it was measured in people training while eating enough to hold their weight, not in people eating less.
- 2.4 g/kg/day against 1.2 g/kg/day1.09 g/lb against 0.55 g/lb
Measured in
40 young men, 20 per group, in a 4 week study eating 40 percent less than they needed and training six days a week, with body make-up measured by a detailed four-part method
The high protein group gained 1.2 kg of lean mass while eating less. The lower protein group gained 0.1 kg. The high protein group also lost more fat, 4.8 kg against 3.5 kg.
Study in peopleHigher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial (2016)What this does not show
Four weeks, young men, food provided, and a training load most people will not match. It shows that eating less changes the answer. It does not show that 2.4 g/kg is the best amount, or that the result holds for a year.
- 2.3 g/kg/day against 1.0 g/kg/day1.05 g/lb against 0.45 g/lb
Measured in
20 lifting athletes, 10 per group, two weeks at 60 percent of their usual calories
Lean mass loss was 0.3 kg on the high protein diet and 1.6 kg on the comparison diet. Total weight loss was 1.5 kg against 3.0 kg, so most of the extra weight the comparison group lost was lean tissue.
Study in peopleIncreased protein intake reduces lean body mass loss during weight loss in athletes (2010)What this does not show
Two weeks and 20 people. It also found people felt more tired on the high protein diet, which is reported here because it was in the results.
- 0.8 against 1.6 against 2.4 g/kg/day0.36 against 0.73 against 1.09 g/lb
Measured in
39 adults split into three groups: 10 days eating enough to hold their weight, then 21 days eating 40 percent less
The only study that put a middle group between the two numbers people argue about. Both 1.6 and 2.4 g/kg protected lean mass better than the RDA, and kept up the muscle-building response to a protein-rich meal, which was dulled at 0.8. Everyone lost the same 3.2 kg of body weight whatever their protein. What differed was what that weight was made of.
Study in peopleEffects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial (2013)What this does not show
It also found no difference it could detect between 1.6 and 2.4. This is the most direct test there is of whether going above roughly 1.6 g/kg while eating less buys anything more, and it did not find that it does. Twenty-one days, 39 people.
- 2.2 g/kg/day as the top of the likely range1.00 g/lb
Measured in
8 male bodybuilders with three or more years of training, 42 separate tracer tests across intakes from 0.1 to 3.5 g/kg a day, on a rest day
A different method entirely. Instead of counting protein in and out, it tracks a tagged protein building block in the breath. It gave an average need of 1.7 g/kg a day, with the top of the likely range at 2.2. That is roughly 2.6 times the current recommendation, measured on a day these men did not train.
Study in peopleIndicator amino acid-derived estimate of dietary protein requirement for male bodybuilders on a nontraining day is several-fold greater than the current recommended dietary allowance (2017)What this does not show
Eight men, one rest day, and an estimate of need rather than a measured effect on muscle. Its value is that the method has nothing in common with anything else on this page, and it lands on the same top figure.
- 2.3 to 3.1 g/kg of fat-free mass per day1.05 to 1.41 g/lb of fat-free mass
Measured in
Six studies of lean, weight-trained adults eating less than they needed, covering 13 study groups
The recommendation the authors landed on, scaled up for how hard the calorie cut is and how lean the person already is. The one group that was lean, truly eating less, and still held on to its lean mass was the group eating the most protein in the review.
Review of studiesA systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes (2014)What this does not show
This is per kilogram of lean mass, not per kilogram of body weight, and that difference is the whole point. It was worked out in lean, trained athletes, which is not most people reading it.
- 2.6 to 3.3 g/kg/day for four months1.18 to 1.50 g/lb
Measured in
12 weight-trained men who tried both diets in turn, two 8 week periods, with full blood panels including cholesterol
No change in cholesterol or blood fats, and no change in kidney or liver tests, at more than four times the RDA. No change in body make-up or performance either.
Study in peopleThe effects of a high protein diet on indices of health and body composition: a crossover trial in resistance-trained men (2016)What this does not show
Twelve healthy young men with normal kidneys, for four months. It is evidence against short-term harm in that group. It is not evidence about people who already have kidney disease, and it is not a long-term study.
- 1.5 g/kg/day or more, against lower intakes0.68 g/lb or more
Measured in
1,358 people across 28 trials in adults without kidney disease, pooled
The kidney question, answered at the scale it deserves. The change in how well the kidneys filter did not differ between higher and lower protein intakes, and the small gap found could have been chance. After the diets, filtering was slightly higher on high protein, which the authors read as a normal adjustment, not injury.
Review of studiesChanges in kidney function do not differ between healthy adults consuming higher- compared with lower- or normal-protein diets: a systematic review and meta-analysis (2018)What this does not show
Every study in it was in adults without kidney disease, and the conclusion is limited to them. It says nothing about anyone whose kidneys already work less well, and the authors note an unclear risk of bias in how people were picked for the included studies.
Questions people ask about this
- Is one gram per pound of bodyweight the same as one gram per pound of goal weight?
- No, and the difference is the whole point. The common version of the rule scales to what you weigh now. That means a person carrying a lot of fat works out a target their lean tissue does not justify. Scaling to goal weight comes close to scaling to lean mass, which is what sports nutrition research actually scales to.
- Does more protein than 1.6 g/kg do anything?
- For building muscle while eating enough to hold your weight, the review that pooled the studies found no further gain above roughly that figure. But that cut-off point did not pass the usual test for being more than chance. Its likely range ran up to 2.2 g/kg, and its authors recommended about 2.2 in their discussion. For people eating less than they burn, 2.3 to 2.4 g/kg clearly beat 1.0 to 1.2 g/kg. The one study with a middle group found 1.6 and 2.4 no different. So the gap between them is truly unsettled, not decided.
- Will a high protein diet damage my kidneys?
- In people with healthy kidneys, no study shows that it does. A review that pooled 28 studies in 1,358 adults without kidney disease found no difference in the change in kidney filtering rate between higher and lower protein intakes. That evidence is limited to people without kidney disease. It does not carry over to anyone whose kidneys already work less well. For them, how much protein to eat is a medical decision.
- Why is the RDA so much lower than any of these numbers?
- Because it answers a different question. The RDA came from nitrogen balance studies, which track the nitrogen from protein going into and out of the body. It is the intake at which 97.5% of inactive adults stop losing body nitrogen. It is the floor for avoiding a shortfall, not an estimate of the intake that best builds or keeps muscle. Its authors never presented it as one.
- Does it matter how I spread protein across the day?
- It matters less than the daily total, which is the thing to get right first. The research on spreading it out is covered separately once the studies have been checked.
Where this sits in the protocol
Protein is the floor the rest of it stands on. It is the thing that decides whether the weight lost is fat or muscle. That is the difference between two results people call the same thing.