How much protein in grams do I need at 103 kg on 1,400 kcal a day?

Setup, so nobody has to ask: 103 kg · 1,400 kcal.

The units are where I keep going wrong, so please be explicit about them.

I have sanity-checked the order of magnitude and it seems right, which is not the same as being right.

How many significant figures are actually justified here?

165 to 227 g a day. The range the resistance-training literature supports is 1.6 to 2.2 g per kilogram, which at 103 kg is 165–227 g. At 4 kcal per gram that is 659–906 kcal, or 47–65 per cent of a 1,400 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 short version: total daily protein first, per-meal distribution second, timing a distant third.

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.

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.

Nothing here is dietetic or medical advice.

Plan protein first in the day; with suppressed appetite it will not happen otherwise.

edited 20 Apr 2026 by Dr_Yusuf_Adeyemi — updated for the 2026 guidance change

Answering this needs to know whether appetite is suppressed, because in this class the practical problem is achieving intake rather than choosing a target.

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.

The part that matters: 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.

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.

Healthy kidneys tolerate this fine. Diseased ones are a clinical question.

Start with which body weight the target is calculated from, because using total weight in someone with substantial adiposity inflates the number without benefit.

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.

Hydration requirements rise modestly with protein intake because urea excretion increases, which is a real effect and a small one.

Per-meal saturation is real. One enormous serving does not do the job of three.

Worth being precise here: plant-based patterns need somewhat higher totals and more attention to leucine content per serving to produce an equivalent response.

High protein intakes do not damage healthy kidneys in the published evidence; existing kidney disease is a genuine exception and is a clinical question.

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.

In practice, 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.

Systematic reviews of high-protein intake in people with normal renal function have not found evidence of harm to kidney function.

Research-use compounds are not approved for human use, and no supplement substitutes for total intake.

Plant-based patterns need a higher total and more attention per serving.