There is a number everyone wants and the research will not give: a single figure, for you, in grams. What it gives instead is a range, and a fairly wide one, inside which the differences are smaller than the difference between hitting a target and not.
This is general nutrition information, not medical advice. If you have kidney or liver disease, are pregnant, or are managing any health condition, these numbers may not apply to you — talk to a doctor or dietitian.
The floor is not the target
The figure in most official dietary guidance is around 0.8 g per kilogram of bodyweight per day. It is widely misread. That number is a population-level minimum designed to prevent deficiency in sedentary adults. It is the amount below which things go wrong, not the amount at which things go well.
If you train, or you are trying to keep muscle while losing fat, or you are over about sixty, the useful range is higher.
The range that is actually supported
| Situation | Per kg of bodyweight | For 75 kg |
|---|---|---|
| Sedentary, maintaining | 0.8 – 1.0 g | 60 – 75 g |
| Exercising regularly | 1.4 – 1.8 g | 105 – 135 g |
| Building muscle | 1.6 – 2.2 g | 120 – 165 g |
| Losing fat, keeping muscle | 1.8 – 2.4 g | 135 – 180 g |
| Over 60, maintaining muscle | 1.2 – 1.6 g | 90 – 120 g |
1.6 g per kilogram is the figure most often quoted for people who train, and it is a reasonable default because the meta-analyses tend to show the returns flattening somewhere close to it. Past roughly 1.6 the curve gets very flat; there is likely still something there, which is why the ranges above go higher, but it is a small something compared with the gap between 0.8 and 1.6.
Why the dieting number is highest
It looks backwards that losing fat needs the most protein. It is not. In a calorie deficit your body is looking for tissue to break down, and muscle is a candidate. Higher protein plus resistance training is what pushes that loss towards fat instead.
Protein is also the most satiating of the three macros per calorie, which matters more when there are fewer calories to go round. It is the one you least want to cut when cutting.
Where the precision actually matters
People spend a lot of attention on questions whose answers barely move the outcome, and little on the one that does. Roughly, in order:
- Hitting your total most days. This is nearly all of it. A 1.6 g/kg target hit five days a week averages lower than a 1.4 g/kg target hit every day.
- Spreading it across the day. Real but second-order: three or four servings of 25–40 g beats 110 g at dinner. Worth doing, not worth agonising over.
- Protein quality. Matters if your intake is mostly plant-based and narrow, because you need a bit more total and a wider spread of sources. Largely irrelevant if you eat animal protein or a varied mix.
- Timing around training. Almost nothing, once the daily total is adequate. The anabolic window is far wider than it was sold as.
The person averaging 150 g a day without thinking about it is winning against the person optimising a 165 g target they hit twice a week.
Is more dangerous?
For healthy people with normal kidney function, high protein intakes — studied up to around 2.5–3 g/kg — have not been shown to harm kidney function. The worry comes from advice correctly given to people who already have kidney disease, which then got generalised to everyone. If you have existing kidney or liver disease this genuinely does apply to you, and it is a conversation with a doctor rather than an app.
The practical ceiling is usually that protein crowds out other food and gets expensive, not that it is risky.
What to do with this
- Take your bodyweight in kilograms. Multiply by 1.6 if you train, 1.2 if you do not, 2.0 if you are dieting and lifting.
- Divide across your meals so each lands somewhere around 25–40 g.
- Work out, once, which foods get you there — then stop recalculating it daily.
That third step is the one apps usually skip. It is the whole of what Protn does: you give it the target and the foods, and it works out the portions so that the number is met by a menu rather than by vigilance.