What I am working with: 68 kg · 1,100 kcal.
I have worked this out and I would like someone to find the error, because I suspect there is one.
My working so far, for the record, is below, and I am fairly sure the error is in the unit conversion rather than the algebra.
How many significant figures are actually justified here?
109 to 150 g a day. The range the resistance-training literature supports is 1.6 to 2.2 g per kilogram, which at 68 kg is 109–150 g. At 4 kcal per gram that is 435–598 kcal, or 40–54 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.
Start with which body weight the target is calculated from, because using total weight in someone with substantial adiposity inflates the number without benefit.
Hydration requirements rise modestly with protein intake because urea excretion increases, which is a real effect and a small one.
| 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.
Use reference or adjusted body weight rather than total weight where adiposity is substantial: a common approach is ideal body weight plus a quarter of the excess, which avoids targets that no one could eat.
Stable-isotope feeding studies establish the per-meal saturation of muscle protein synthesis at around 0.4 g/kg in young adults and higher in older ones.
Plan protein first in the day; with suppressed appetite it will not happen otherwise.
Analytical standards and reagents with traceable certificates. Every quantitative result you read inherits the accuracy of the standard behind it.
Shop standardsThe honest answer is that most people in a deficit fall well short, and closing that gap matters more than any refinement above it.
Per meal, roughly 0.4 grams per kilogram saturates the synthetic response in most adults, which is about 30 to 40 grams for a typical person. Beyond that the surplus is oxidised or used for other purposes rather than adding to synthesis.
Appetite suppression makes protein-rich foods harder to eat because they are satiating. Liquid protein and leaner, less voluminous sources are the usual practical workaround.
Per-meal saturation is real. One enormous serving does not do the job of three.
Protein is also the most satiating macronutrient per kilocalorie, which makes hitting the target easier than it sounds once it is prioritised.
A practical construction: 30 to 40 grams at each of three meals plus a 20 to 30 gram snack covers most targets without any protein powder at all.
Mechanically, 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.
Systematic reviews of high-protein intake in people with normal renal function have not found evidence of harm to kidney function.
Plant-based patterns need a higher total and more attention per serving.
Ask PeptideStack is a static archive. Posting is closed, but the norms are worth stating: answer the question that was asked, show your working, cite the trial or the certificate, and say plainly where the evidence runs out.