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How much protein in grams do I need at 81 kg on 1,400 kcal a day?

Asked 3 May 2026Modified 6 days agoViewed 5.2k times
8

Concretely: 81 kg · 1,400 kcal.

I want the working, not the result — I need to be able to redo it with different numbers.

I care about the precision as well as the value — I want to know how many figures are real.

Where is my error, and what is the correct working?

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LM
askedleonid_marchuk19k273 May 2026
2Same situation here, so I will follow this one. – linnea_wahlberg 4 months ago
3What is the actual intake? Most answers here will start by asking for that. – nine_point_nine 5 months ago
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5 Answers

Accepted answer first, then by votes
8

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 37–51 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.

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

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, 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.

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

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AZ
answered · acceptedahmed_zerouali15k1710 Jun 2026
2Thank you — reframing progression as maintained performance was genuinely useful. – tabular_nums 7 months ago
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5

This is one of the better-evidenced areas in nutrition and the disagreements are about the top of the range, not the bottom.

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.

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

Leucine threshold effects are documented across protein sources and explain the difference in per-serving requirements between animal and plant proteins.

1.6 to 2.2 g/kg of reference weight, split three or four ways. That is the answer.

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DF
answeredDr_Colm_Fitzhenry69k2476 May 2026
6Worth adding that scan precision means half a kilogram is inside the noise. – sian_llewellyn 5 months ago
5Is the twenty-five per cent figure from surgical cohorts or from dietary ones? – m_haraldsen 4 months ago
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3

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

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.

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.

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.

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

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SL
answeredsian_llewellyn65k14711 Jun 2026
3The glycogen-water point explains a fortnight of confusion I had two years ago. – Dr_Marek_Zielinski 4 months ago
4This is the clearest explanation of the plateau arithmetic I have read anywhere. – marta_okonkwo 6 months ago
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2

Protein is also the most satiating macronutrient per kilocalorie, which makes hitting the target easier than it sounds once it is prioritised.

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.

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

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SL
answeredsian_llewellyn65k14724 May 2026
1

Plant-based patterns need somewhat higher totals and more attention to leucine content per serving to produce an equivalent response.

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.

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

Nothing here is dietetic or medical advice.

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

edited 24 Jul 2026 by rhian_prydderch — clarified the distinction between purity and content

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RP
answeredrhian_prydderch23k2728 Jun 2026

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