How much protein you need
The official floor and the practical target are quite different numbers, and conflating them causes most of the confusion in this area.
The Recommended Dietary Allowance is 0.8 g per kilogram of body weight. That figure is the amount sufficient to prevent deficiency in most healthy sedentary adults — a minimum to avoid a problem, not an amount optimised for anything.
For people who train, the International Society of Sports Nutrition position stand recommends roughly 1.4–2.0 g/kg for building and maintaining muscle, with higher intakes justified during a calorie deficit. Worked example: a 70 kg person aiming for 1.8 g/kg needs 70 × 1.8 = 126 g of protein daily.
Where the benefit plateaus
More is not indefinitely better, and it is worth knowing where the curve flattens. A systematic review and meta-analysis in the British Journal of Sports Medicine, pooling data from 49 studies, found that protein supplementation significantly improved strength and lean mass gains from resistance training — and that benefits appeared to plateau at around 1.6 g/kg in the studies analysed.
Two honest caveats on that plateau. It applies to muscle gain in people eating adequate calories; during a deficit, higher intakes look more useful for preserving lean mass, which is why 1.8–2.2 g/kg is a reasonable target when dieting. And group averages hide individual variation. But if you are eating 3 g/kg and finding it a burden, the evidence does not support the effort.
Why protein matters most
- It preserves muscle in a deficit. Combined with resistance training, adequate protein largely determines whether the weight you lose is fat or partly muscle.
- It builds muscle in a surplus, given a training stimulus to direct it.
- It is the most satiating macronutrient per calorie, which makes any calorie target easier to hold.
- It has the highest thermic effect — roughly 20–30% of protein calories are used digesting and processing it, against 5–10% for carbohydrate and 0–3% for fat.
- It becomes more important with age. Older adults show a blunted muscle-protein response to a given dose, so requirements rise rather than fall — relevant to preserving strength and independence later in life.
Distribution and timing
Total daily intake matters most, but distribution has a modest effect. Spreading protein across three or four meals of roughly 25–40 g appears slightly better for muscle protein synthesis than concentrating it in one or two.
The "anabolic window" — the belief that protein must be consumed within 30 minutes of training — has been substantially walked back. Total daily intake dominates, and the window is far wider than once claimed. If it is convenient to eat after training, do; if not, it will not undo your session.
Good sources
Chicken, fish, eggs, lean beef, Greek yoghurt, cottage cheese, milk, tofu, tempeh, edamame, lentils, beans, chickpeas, seitan, and protein powder.
Plant proteins work perfectly well, with two adjustments: they tend to be lower in one or more essential amino acids, and slightly less digestible, so eating a variety across the day and aiming somewhat higher on total intake covers the gap comfortably. Soy, in particular, is a complete protein.
Is high protein safe?
For people with healthy kidneys, yes. The concern that high protein intake damages kidney function comes from research on people who already have kidney disease, in whom protein restriction is genuinely part of management. That finding does not transfer to healthy people, and controlled trials in healthy adults have not shown harm at the intakes discussed here.
If you do have kidney disease, this is a real exception and you should be following advice from your clinician rather than a general calculator.