Protein intake

The 0.8 g/kg RDA is a floor, not a target

The figure most people half-remember — 0.8 grams per kilogram, or 46 and 56 grams a day for women and men — is the amount that prevents deficiency in a sedentary adult. It is the bottom of the range, set to stop something going wrong, not to make anything go right. Nearly every body of evidence on training, ageing or weight loss points higher.

How much protein in a calorie deficit

This is where protein earns its reputation. In a deficit your body is looking for tissue to break down, and protein intake is one of the two levers — resistance training is the other — that decide whether it takes it from fat or from muscle. Intakes above roughly 1.3 g/kg are associated with holding onto lean mass; under 1.0 g/kg the risk of losing it rises.

For someone lean and already training, the position stands go considerably higher, to 2.3–3.1 g/kg. That band is not a general recommendation — it was derived from resistance-trained people deliberately cutting, which is a narrow group.

Building muscle, and where the evidence stops

The meta-analysis most often cited pooled 62 studies and found the benefit flattening out near 1.6 g/kg, with the confidence interval reaching to about 2.2. Beyond that there is no measured advantage in the trials we have. Higher is not harmful for healthy kidneys; it is just not doing anything, and it is displacing carbohydrate and fat that would be.

If you carry a lot of body fat, which weight do you multiply?

Total bodyweight. That is the honest default, and it is what this page uses — until you tell it otherwise. The problem is that fat tissue has very little protein requirement, so multiplying it alongside everything else overestimates the need at high body fat. Enter a body fat percentage above and the multiplier moves onto lean mass at 1.5 times, which is the usual clinical workaround. The two can differ by 30 grams a day or more.

Spreading it across the day

The per-meal figure here is 0.4 g/kg across four or more meals, from the work by Schoenfeld and Aragon. The effect of distribution is real but modest — hitting the daily total matters considerably more than how neatly you divide it. If four meals does not suit your life, three will not undo the week.

Is high protein bad for your kidneys?

This is the most-asked question on the subject and it deserves a straight answer. In people with healthy kidneys, randomised trials have not shown higher protein intakes damaging kidney function. The confusion comes from the opposite direction: people whoalready have chronic kidney disease are often put on a protein restriction, typically 0.6–0.8 g/kg, because their kidneys cannot clear the load. A treatment for existing disease became, in retelling, a warning for everyone.

So: if you have kidney disease, are on dialysis, or have had a transplant, the number on this page is not for you — your nephrology or dietetic team sets it. Liver disease and inborn errors of amino-acid metabolism are the same. Pregnancy, breastfeeding and under-18s have their own requirements. Most trials in healthy adults are short, which is worth knowing before treating any of this as settled.

Once you have a figure, the macro calculator fits it alongside carbohydrate and fat inside a calorie target.