Accepted answer
130 to 178 g a day. The range the resistance-training literature supports is 1.6 to 2.2 g per kilogram, which at 81 kg is 130–178 g. At 4 kcal per gram that is 518–713 kcal, or 47–65 per cent of a 1,100 intake — which is why protein has to be planned first at this energy level rather than fitted in afterwards. Split it across three or four servings; roughly 0.4 g/kg per meal saturates the synthetic response and the surplus in one large serving does not carry over.
This is one of the better-evidenced areas in nutrition and the disagreements are about the top of the range, not the bottom.
The leucine threshold for triggering the response is around two and a half to three grams per meal. Thirty grams of most animal protein reaches it; thirty grams of many plant proteins does not, which is why plant-based targets run higher.
Protein target arithmetic
| Body mass | 1.2 g/kg | 1.6 g/kg | 2.0 g/kg | Per meal at 1.6 (÷3) |
|---|
| 62 kg | 74 g | 99 g | 124 g | 33 g |
| 74 kg | 89 g | 118 g | 148 g | 39 g |
| 88 kg | 106 g | 141 g | 176 g | 47 g |
| 103 kg | 124 g | 165 g | 206 g | 55 g |
| 124 kg | 149 g | 198 g | 248 g | 66 g |
At roughly 4 kcal per gram, 141 g of protein is about 564 kcal — a substantial fraction of a 900 kcal budget, which is the real constraint.
Older adults need more per meal to overcome anabolic resistance, with 1.2 to 1.5 g/kg daily commonly quoted for maintenance and more in a deficit.
Leucine threshold effects are documented across protein sources and explain the difference in per-serving requirements between animal and plant proteins.
Nothing here is dietetic or medical advice.
Healthy kidneys tolerate this fine. Diseased ones are a clinical question.