How much protein a day?

EFSA, the European authority, sets the reference intake for protein at 0.83 g per kilo of body weight per day, for every adult; France's ANSES holds the same figure. For 70 kg, that makes 58 g a day.

This figure was calculated for one thing only: that the body does not lose more protein than it receives, in almost everyone. It is a safety floor, not a target. It says nothing about what it takes to keep your muscles as you age, to build them, or not to lose them while dieting.

In the other direction, there is no official upper limit. EFSA considers an intake of up to twice the reference safe in healthy adults, and notes that active Europeans commonly eat that much without harm.

Three situations call for clearly more than the floor. The targets below are those of each field's scientific societies, worked out here for 70 kg.

Sport. The International Society of Sports Nutrition recommends 1.4 to 2 g per kilo for people who train regularly. Beyond that, the gain stops: a meta-analysis of 49 trials sees no further benefit for muscle above roughly 1.6 g per kilo. Training is what builds muscle; protein is only the material.

Dieting. Eating less loses fat, but muscle too. Aiming for 1.2 to 1.6 g per kilo during a diet limits that loss, and is more filling: it is the lever covered in Losing weight.

Pregnancy and breastfeeding. EFSA adds to the reference 1 g a day in the first trimester, 9 g in the second and 28 g in the third, then 19 g a day during the first six months of breastfeeding.

With age, muscle responds less well to protein. To trigger the same muscle building, an older man needed in a Canadian study about 0.4 g of protein per kilo in one meal, against 0.24 g in a young man: nearly twice as much.

Yet it is often the age when people eat less, meat in particular. Muscle then melts away slowly, a fraction of a percent a year, with nothing visible for years. The bill comes late: less strength to get up, falls, loss of independence. It is the same silent pattern as calcium and bone, described in Minerals.

The PROT-AGE expert group therefore recommends 1 to 1.2 g per kilo over 65, and 1.2 to 1.5 g with chronic illness. EFSA, for its part, kept 0.83 g for every age, finding the evidence insufficient to set another figure. Both positions coexist, and in practice they lead to the same advice: do not go below 1 g.

Protein is not enough on its own: without physical effort, even a rich plate does not hold on to muscle. Brisk walking, climbing stairs, getting up from a chair without using your hands are part of the same prescription.

Muscle does not store protein: it takes what it needs at the meal, and the surplus is burned or converted. Hence the point of spreading it out. In young adults, the effect on muscle levels off around 20 to 25 g per meal; after 60, it takes more like 30 g.

The French-style breakfast breaks this pattern. Bread, jam, milky coffee: barely 10 g of protein. Dinner, meanwhile, often brings 40 or 50. Over the day, the total can be fine while two meals out of three stay below the threshold.

Studies on spreading do not all point the same way, and the daily total remains the first criterion. But moving part of dinner's protein to the morning costs nothing, and it is also what carries you to lunch without an energy dip: see Gaining energy.

The portion that provides 25 g of protein, one meal's target, and the calories that come with it. The amounts are calculated from the site's database; tap a food to open its sheet.

Fish, lean meat and hard cheeses fit in a small portion. Eggs already take three to four, fresh dairy a large bowl. Pulses get there too, but with a clearly larger volume and more calories, and a less complete protein: that is why pairing them with a grain matters, as Protein: quantity is not quality explains.

Bread is not in the table as a protein source: it is one, but the 290 g it would take is nothing like a reasonable meal. It adds a top-up, not the foundation.

The fear comes up often: lots of protein would wear out the kidneys. In a healthy person, the data do not bear it out. A 2018 meta-analysis comparing high intakes, above 1.5 g per kilo, with normal intakes finds no difference in kidney function.

The kidney does filter more after a protein-rich meal, but that is a normal adaptation, like the heart speeding up during exercise. Things change with existing kidney disease: then protein intake is a matter for the doctor, and usually downwards.

0.83 g per kilo is a floor, not a target: it is what avoids losing protein, not what maintains muscle.

Over 65, aim for at least 1 g per kilo, and move: muscle is lost silently, and effort is what holds on to it.

Sport and dieting call for more, up to 1.6 g per kilo; beyond that, muscle gains nothing more.

Breakfast is the meal to fix: 20 to 30 g of protein in the morning rebalances the day.

Healthy kidneys have nothing to fear from a high intake; kidney disease does.