How much protein you actually need (the number moves, and here's why)

The Recommended Dietary Allowance for protein is 0.8 grams per kilogram of body weight per day. That figure gets quoted as a target constantly, including by people who ought to know better, and it was never designed to be one. It is the amount that prevents measurable deficiency in 97.5% of healthy adults — a floor under a cliff, not a place to stand.

For a 70kg adult that is 56 grams a day. It is achievable without thinking. It is also, for most of the people I see, meaningfully below what would serve them, and the gap widens with every decade of age.

Where the higher numbers come from

Three separate lines of evidence push the useful range upward, and they are worth distinguishing because they apply to different people.

Anabolic resistance with age

Older muscle responds less to a given dose of protein. The same 20 grams that maximally stimulates muscle protein synthesis in a 25-year-old produces a blunted response at 70 — you need something closer to 35 or 40 grams in a single sitting to get the same effect. This is well replicated and it is the strongest argument for higher intake in older adults, where the PROT-AGE consensus recommends 1.0 to 1.2 g/kg, and 1.2 to 1.5 for those who are active or unwell.

Energy restriction

In a calorie deficit, protein requirements rise, because some of it is being burned for fuel and because you are trying to hold on to lean tissue while losing mass. The range I use for clients actively losing weight is 1.2 to 1.6 g/kg, and higher — toward 1.8 — for those on GLP-1 medications, where the loss is faster and the lean-mass fraction is a real concern.

Resistance training

The meta-analytic answer here is unusually clean: benefits to lean mass and strength plateau at around 1.6 g/kg per day, with a confidence interval extending to about 2.2. Above that there is no signal. If someone is eating 3 g/kg, they are not doing harm, but they are eating expensive protein for no additional return.

Distribution matters more than most people think

A hundred and twenty grams of protein eaten as 10 at breakfast, 25 at lunch, and 85 at dinner is not equivalent to the same total spread evenly. Muscle protein synthesis is a threshold-and-refractory system: below roughly 20 to 25 grams you do not fully trigger it, and above about 40 in one sitting the additional amount is mostly oxidised rather than used for building.

So three or four occasions of 25 to 40 grams beats one enormous evening dose, and the meal almost everyone under-eats is breakfast. The typical American breakfast — cereal, toast, fruit, coffee — lands around 8 to 12 grams. Fixing breakfast alone typically adds 20 to 25 grams a day and is the single highest-yield change I make in a first session.

What 30 grams actually looks like

• Four large eggs — 24g. Add a slice of cheese and you are there.
• A cup of plain Greek yoghurt (0% or 2%) — 20–23g. With a tablespoon of hemp hearts, 26g.
• A 4oz chicken breast — 35g.
• A cup of cooked lentils — 18g. With a slice of wholegrain toast, 24g.
• A cup of cottage cheese — 25g, which is why it has had a resurgence and why the resurgence is deserved.
• A scoop of whey — 24g, and there is nothing wrong with this if the alternative is 8g.

The satiety argument, which is the practical one

Set aside muscle for a moment. Protein is the most satiating macronutrient per calorie by a considerable margin, and in controlled feeding studies raising protein to around 30% of energy produces spontaneous reductions in total intake without anyone being asked to restrict anything.

This is why the first change I make for a client who wants to eat less is almost never "eat less." It is to add protein to breakfast. The reduction happens downstream, at 4pm, without a decision being required — and decisions, at 4pm, are the scarcest resource anybody has.