How Much Protein Do You Need Per Day?

Last updated: August 2026 · Reviewed by the FactoWiki Editorial Team for clarity and source accuracy

0.8 g per kg is the minimum to prevent deficiency, not an optimum. For building or maintaining muscle, 1.6–2.2 g per kg is the evidence-based range, with meta-analysis putting the point of diminishing returns around 1.6 g/kg. Older adults need more, not less.

Why the RDA is misleading

0.8 g per kg is set to prevent deficiency in most of the population, which is a different question from what optimises muscle, satiety or healthy ageing. Treating it as a target rather than a floor is one of the more consequential misunderstandings in nutrition.

What the evidence supports

The Morton 2018 meta-analysis of 49 randomised trials found protein supplementation augmented resistance-training gains, with a breakpoint around 1.62 g/kg/day beyond which no further benefit was detectable. In a calorie deficit, higher intakes help preserve muscle. Practical guidance of 1.6–2.2 g/kg covers most goals.

Age changes the answer

Older adults show anabolic resistance — the same protein dose produces a smaller muscle protein synthesis response. That argues for both higher total intake and a larger amount per meal, often 30–40 g rather than 20 g. Given that sarcopenia predicts frailty and falls, this is one of the more important nutritional points in later life.

Key ingredients to understand

The ingredients most relevant to this question, with what the evidence actually supports:

• Whey Protein — Whey is a complete, rapidly absorbed protein high in leucine, and it has as strong an evidence base for muscle protein synthesis as anything in…
• Pea Protein — Pea protein is the best-evidenced plant protein for muscle, performing comparably to whey in head-to-head training trials. It is lower in…
• Creatine Monohydrate — Creatine monohydrate is the most researched sports supplement in existence, with hundreds of trials supporting increased strength and lean mass…
• Casein Protein — Casein is the slow-digesting milk protein, forming a gel in the stomach that releases amino acids over hours. That makes it well suited to…

Frequently asked questions

Do I need to spread it across meals?

Distributing protein across 3–4 meals appears modestly better than concentrating it in one, particularly for older adults.

Is high protein bad for kidneys?

Not in people with healthy kidneys. That advice comes from people who already have kidney disease.

Should I use body weight or lean mass?

At higher body fat levels, lean mass or goal weight gives a more sensible number.

This article is general information, not medical advice. FactoWiki may earn a commission from links on product review pages (never on comparisons). Always check with a qualified healthcare professional about your own situation.