More protein stops helping a long way below where the internet puts it.

Where the line flattens

The reference point most often cited is a 2018 meta-analysis by Morton and colleagues, pooling dozens of resistance-training trials. Protein intake improved strength and lean mass gains, as everyone expects — and the improvement stopped climbing at roughly 1.6 g per kg of bodyweight per day. The confidence interval reached higher, which is why careful summaries say “about 1.6, possibly up to 2.2” rather than naming one figure.

That is the whole basis for the number on this site. Not that more is harmful, and not that more is pointless in every case — but that past that region, the measured return on an extra twenty grams a day is small enough that the trials stop being able to see it.

Why the cutting number is higher

In a deficit the job changes. You are no longer trying to add tissue; you are trying to lose fat without losing muscle alongside it, while short of energy. Protein is the lever that matters most for that, and the recommendations for lean people dieting hard run well above the training-for-growth figure — Helms and colleagues, reviewing the literature for lean athletes in a deficit, landed in the region of 2.3–3.1 g per kg.

That range is per kilo of fat-free mass, not bodyweight, and the difference is not cosmetic. For someone carrying a lot of fat, fat-free mass can be twenty kilos below bodyweight, and quoting a fat-free-mass number against a bathroom scale would overshoot badly. This site does not know your body composition, so it works in bodyweight and picks 2.2 — comfortably above the growth plateau, and still sane for someone who is not lean.

There are two other reasons the deficit number is the higher one, and both of them are about making the deficit survivable rather than about muscle. Protein is the most filling of the three macronutrients per calorie, which matters when calories are the constraint. And digesting it costs more than digesting the other two — a meaningful slice of protein calories is spent processing the protein itself, which is a real effect and a small one, not a diet mechanism.

Per meal, and the window that is not a window

Total intake across the day is what the evidence supports most strongly. How it is split matters, but far less, and in a specific way.

1. There is a per-meal dose worth hitting. The working figure in the literature is around 0.4 g per kg per meal, across roughly four meals, which lands a 75 kg person near thirty grams a sitting and adds up to about 1.6 g/kg for the day. The arithmetic is not a coincidence — the per-meal advice and the daily total were derived to agree.
2. The thirty-gram cap is a misreading. The claim that the body “cannot use” more than about thirty grams at once comes from studies of how much protein synthesis a single dose maximally stimulates. Nothing is wasted past that point: the rest is still digested, still absorbed, and still counts toward the day.
3. The post-workout window is hours, not minutes. Reviews of the timing literature find the effect much wider and much weaker than the thirty-minute rule implies, and largely explained by total daily intake. If you trained fasted, eat soon. Otherwise the urgency is marketing.
4. Even distribution beats one large meal. This is the part of the timing story that survived. Four moderate servings out-perform one enormous one for the same total, which is why the plan on this site talks about four meals rather than about a window.

Four words used as if they meant the same thing

Most confusing protein advice is a category error. These four get swapped for one another constantly, and they are not interchangeable.

The last one does most of the damage. A food, a supplement or a timing trick that raises protein synthesis for a few hours has not been shown to build anything. Synthesis goes up after every adequate meal. What gets built is the balance of synthesis against breakdown, over months.

Things said about protein that the evidence does not support

1. That it damages healthy kidneys. Controlled trials and meta-analyses in people with normal kidney function have not found harm from high-protein diets. This does not extend to people with existing kidney disease, for whom protein intake is a medical question with a real answer that belongs to their doctor.
2. That plant protein does not count. Individual plant sources are often lower in one or another essential amino acid, and less of what is eaten gets absorbed. Both gaps close with a varied diet and a somewhat higher total, which is a reason to eat a bit more rather than a reason to write the category off.
3. That you need a shake. Powder is food that has had the water and the cooking removed. It is convenient and it is cheap per gram, and it does nothing that the same protein in solid form does not do.
4. That more is always better. This is the one the whole page is about. Past the plateau, extra protein is mostly displacing the carbohydrate that fuels the training session — a trade, not a free addition, because the calories still have to come from somewhere in the day.

What this plan actually does with the number

1. Protein is set first, from bodyweight. 1.8 g per kg to gain or hold, 2.2 in a deficit. It is a floor, not a target to be hit exactly, and going twenty grams over on a given day is not an error.
2. Fat is set second, also from bodyweight, and held between twenty and thirty-five per cent of the day’s calories so that it cannot be squeezed to nothing.
3. Carbohydrate takes whatever is left. It is the only one of the three that is not given a floor, which makes it the one that moves when the calorie target moves. That is deliberate: it is the one that fuels the sessions and the one you can most afford to vary.
4. Protein is capped at forty per cent of the day. At a heavy bodyweight in a deep deficit, g/kg protein plus g/kg fat can exceed the whole calorie target and drive carbohydrate negative. The plan clamps it and says so on screen rather than quietly printing an impossible number.

This is general information, not medical or dietary advice. Every figure here is a population average from published research, and you are not a population average. Kidney disease, liver disease, diabetes, pregnancy and a long list of medications all change the right answer. If any of those apply, the number that matters is the one your doctor gives you, not the one on this page.