How Much Protein Do You Actually Need Per Day?

The honest answer is that it depends on who is asking, and that the official number was never designed to answer the question most people are actually asking.

The RDA is a floor, not a target

The Recommended Dietary Allowance for protein is 0.8 g per kilogram of bodyweight per day. For a 75 kg adult that is 60 g.

What matters is what that number was derived to do. The RDA is the amount sufficient to meet the needs of about 97.5 per cent of healthy people for nitrogen balance — that is, to prevent deficiency. It was never derived as an intake that optimises lean mass, strength or physical function. The average requirement it is built on sits lower still, around 0.66 g per kilogram.

Treating a deficiency-prevention threshold as a performance target is the single most common error in this area.

The method underneath it has also been challenged. Studies using indicator amino acid oxidation — a different technique with a different endpoint — consistently produce higher requirement estimates, particularly in older adults. Those studies are small, often six to twenty participants, and short. They are suggestive rather than definitive, and it is worth saying so.

What changed in 2026

The 2025 to 2030 Dietary Guidelines for Americans moved the conversation officially, raising protein recommendations for specific groups. A Perspective published in The Journal of Nutrition in July 2026 by Pasiakos and colleagues supported the direction while pushing back hard on universality: the evidence base was generated primarily for specific populations, not all Americans, and what is optimal for one group should not be assumed optimal for everyone.

That is roughly where the science sits. The number moved up, and the people who study protein for a living immediately said the evidence does not yet support applying it to everyone.

The number for people who train

The figure most often quoted is 1.6 g per kilogram per day, and it comes from Morton and colleagues (2018), a meta-analysis of 49 randomised trials covering 1,863 participants.

Two things are worth knowing about it.

First, what protein supplementation actually delivered in those trials: an average of 0.30 kg of extra fat-free mass and 2.49 kg on one-rep max, over and above resistance training alone. That is the whole effect. It is real and it is small, and the authors were explicit that resistance training itself is by far the more potent stimulus.

Second, the 1.6 figure is less solid than its ubiquity suggests. The breakpoint was not statistically significant, and its confidence interval ran from 1.03 to 2.20 — spanning almost the entire range of intakes studied. The data cannot actually locate the plateau precisely.

Subsequent work has pushed against a hard ceiling. Tagawa and colleagues (2021) analysed 105 trials with a modelling approach that does not assume a breakpoint and found a continuous relationship: benefit diminishes above roughly 1.3 g per kilogram but does not stop, with a positive slope persisting well beyond 1.6. A 2025 review in energy-restricted trained individuals found fat-free mass loss prevented up to about 1.9 g per kilogram, with higher intakes still associated with larger gains.

The defensible position: 1.6 g per kilogram is a reasonable floor for people training seriously, not a ceiling. Somewhere between 1.6 and 2.2 g per kilogram — about 0.73 to 1.0 g per pound — covers the evidence, with clearly diminishing returns at the top. The old “a gram per pound” heuristic sits at the upper end of that range and is defensible rather than absurd.

If you carry substantial body fat, scaling to fat-free mass rather than total bodyweight is more accurate and will give you a lower, more sensible number.

Per meal, and the myth about 30 grams

You have probably been told your body can only use 20 to 30 g of protein at a sitting and the rest is wasted. It is not true, and the study that dismantled it is worth knowing.

Trommelen and colleagues (2023) gave participants 0, 25 or 100 g of protein after resistance exercise and tracked the response for twelve hours with repeated blood and muscle sampling. The 100 g dose produced a greater and substantially more prolonged anabolic response — muscle protein synthesis was about 40 per cent higher during hours four to twelve. Under 15 per cent of the ingested protein went to oxidation. You do not, as the saying goes, just pee it out.

That is one acute study in young men and it does not prove one enormous meal is optimal. But it removes the hard ceiling, and it is worth noting that the myth it corrects has been used for years to sell more frequent shakes.

The practical guidance still favours spreading protein out, for different reasons. Around 0.4 g per kilogram per meal across four meals is a reasonable structure, which lands you at 1.6 g per kilogram over the day. The International Society of Sports Nutrition position stand suggests 0.25 g per kilogram per meal, or 20 to 40 g in absolute terms, roughly every three to four hours.

Does timing matter? Much less than you were told

The anabolic window — the idea that you must consume protein within 30 to 45 minutes of training — does not survive scrutiny.

A 2013 meta-analysis initially found a small effect of protein timing on hypertrophy. After controlling for total daily protein intake, the effect vanished entirely. Most of the included studies had simply failed to match total protein between groups; the timing groups were eating more protein.

The most recent analysis, published in Nutrients in 2025, compared pre- versus post-exercise protein across five trials with dietary intake controlled. No effect on chest press strength. No effect on lean body mass. The authors concluded that protein timing does not importantly modify exercise-induced changes in lean mass.

The training bout sensitises muscle to protein for at least 24 hours. The window is a day, not an hour.

Pre-sleep protein is the one timing intervention with a plausible independent effect — around 40 g of casein before bed appears to raise overnight muscle protein synthesis — but most of those trials also did not match total daily protein, so treat it as promising rather than established.

If a shake after training is how you reliably hit your daily total, that is a perfectly good reason to have one. Just not the reason you were sold.

Distribution: real, but a second-order problem

Total intake is the main lever. Distribution matters most when total intake is low.

The canonical study is Mamerow and colleagues (2014), a seven-day crossover comparing an even distribution — about 30 g at each of three meals — against a skewed one of roughly 10, 16 and 63 g. Both delivered about the same daily total. Twenty-four-hour muscle protein synthesis was 25 per cent higher on the even pattern.

But a 2021 systematic review of 15 studies found even distribution associated with greater muscle mass in only three of seven studies, and with strength in two of seven, concluding the evidence is insufficient to draw a firm conclusion.

The useful version: adding protein to a dinner that already contains 50 g does very little. Raising breakfast from 10 g to 30 g does something measurable at the same daily total. The real-world problem is the skewed Western pattern — negligible breakfast, enormous dinner — rather than distribution as an abstract principle.

Is high protein bad for your kidneys?

In healthy people with healthy kidneys, the controlled evidence is reassuring. A 2018 meta-analysis of 28 trials covering 1,358 healthy adults compared roughly 1.8 g per kilogram against roughly 0.9 and found no adverse effect on kidney function. A 2024 meta-analysis of six prospective cohorts covering 148,051 people found higher protein intake associated with lower risk of chronic kidney disease.

Now the limits, because they matter. Those trials excluded anyone with existing kidney impairment, protein in the urine, or a history of kidney stones. They ran for months, not decades. And a serious minority of nephrologists argue the reassurance has been oversold — a 2024 paper in Sports Medicine pointed out that the trials in trained athletes were not designed to assess kidney safety at all, and that long-term data on people eating above 1.5 g per kilogram for years essentially does not exist.

If you have kidney disease, diabetes, or a history of stones, protein intake is a conversation for your doctor rather than a blog post.

Putting a number on it

Sedentary, healthy, not trying to change body composition: 0.8 to 1.0 g per kilogram covers you.
Training regularly: 1.6 to 2.2 g per kilogram. Land in the middle unless you have a reason not to.
Losing weight: the upper half of that range, because protein needs rise as calories fall. There is more on that here.
Over 50: higher again, and for reasons worth understanding — covered separately.
Carrying substantial body fat: scale to fat-free mass, not total weight.

Spread it across three or four meals, put a real amount at breakfast, and stop worrying about the clock. Food should do most of the work; a protein powder is a convenience for closing the gap when food does not get you there, which for most people is most days rather than every day. Ours is here, and it will do that job about as well as any other complete protein — which is exactly what Morton and colleagues found.