The specifics, since they change the answer: 81 kg · 1,000 kcal.
I would rather understand the derivation than memorise the outcome.
Two people I asked gave two answers that differ by a factor of ten, which is suggestive.
What is the general form of this calculation?
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 52–71 per cent of a 1,000 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.
The honest answer is that most people in a deficit fall well short, and closing that gap matters more than any refinement above it.
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.
On the detail: 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.
Systematic reviews of high-protein intake in people with normal renal function have not found evidence of harm to kidney function.
The caveat is that anyone with chronic kidney disease has a genuinely different protein calculation and needs it done by a clinician.
1.6 to 2.2 g/kg of reference weight, split three or four ways. That is the answer.
HPLC purity, identity confirmation and quantified content on the vial you actually hold. Reports arrive with the chromatogram attached, not just a number.
Submit a sampleFounded 1998. ISO 9001 and cGMP certified, 1,500+ staff and 200+ patents. The synthesis house behind a great many of the vials that get sent out for testing - batch-specific documentation with every order.
Visit GL BiochemThe short version: total daily protein first, per-meal distribution second, timing a distant third.
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.
Specifically, 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.
Per-meal saturation is real. One enormous serving does not do the job of three.
This is one of the better-evidenced areas in nutrition and the disagreements are about the top of the range, not the bottom.
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.
The relevant detail is that 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.
Meta-analytic estimates place the plateau of the dose-response for lean-mass retention with resistance training around 1.6 g/kg, with a confidence interval extending to about 2.2.
Targets are population estimates; individual requirements vary and there is no cheap way to measure yours.
Healthy kidneys tolerate this fine. Diseased ones are a clinical question.
edited 25 May 2026 by sian_llewellyn — clarified the distinction between purity and content
Protein is also the most satiating macronutrient per kilocalorie, which makes hitting the target easier than it sounds once it is prioritised.
High protein intakes do not damage healthy kidneys in the published evidence; existing kidney disease is a genuine exception and is a clinical question.
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.
Research-use compounds are not approved for human use, and no supplement substitutes for total intake.
Plan protein first in the day; with suppressed appetite it will not happen otherwise.
The relevant physiology is the per-meal saturation of the synthetic response, which is why one large serving does not substitute for three moderate ones.
Hydration requirements rise modestly with protein intake because urea excretion increases, which is a real effect and a small one.
The body-composition substudies in the major programmes consistently report that the proportion of weight lost as fat mass is approximately three quarters or better, with the lean-mass fraction falling within the range seen in dietary weight loss of comparable magnitude[1].
The caveat is that population averages tell you about populations. Your own trajectory is a sample of one and should be read as a trend, not as a deviation from a published mean.
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.