Protein: How Much You Actually Need, and When It Matters

Two very different conversations about protein happen at once, and they rarely meet. In one, a twenty-five-year-old weighs his chicken to the gram, stacks three scoops of powder a day, and worries he isn't getting enough. In the other, an eighty-year-old eats a slice of toast for breakfast, soup for lunch, picks at dinner, and is quietly losing the muscle that keeps her on her feet — and nobody has ever mentioned protein to her at all.

The second person is the one the evidence is actually worried about. Protein is one of those topics where the loudest anxiety and the real risk are pointed in opposite directions. So it's worth getting the numbers straight, and then asking the more useful question: not "how much protein?" but "who is this actually a problem for?"

Where the official number comes from

The UK reference figure, set by the Scientific Advisory Committee on Nutrition, is roughly 0.75 grams of protein per kilogram of body weight per day for adults — about 56 grams for an average man, 45 for an average woman. Most people in the UK comfortably exceed it without trying.

It's worth understanding what that number is, because it's routinely misread. The reference intake is the amount estimated to prevent deficiency in most healthy people — the floor below which things go wrong, not the ceiling for thriving. It was never meant to answer questions about building muscle, recovering from training, or protecting an ageing body. Treating "you don't need more than the RDA" as the end of the conversation is like treating the minimum wage as career advice.

When more is genuinely justified

For people doing regular resistance training, the evidence does support eating more than the reference floor. The sports-nutrition literature, summarised by bodies like the International Society of Sports Nutrition, lands in the region of 1.4 to 2.0 grams per kilogram per day to support muscle growth and recovery — meaningfully above the RDA, and well-evidenced for that specific purpose.

But two honest qualifications keep this in proportion. First, the relationship has a ceiling: beyond a point, extra protein doesn't build extra muscle — it's simply used for energy or excreted, which makes the fourth daily shake an expensive way to produce costly urine. Second, the whole package matters more than the precise gram count. Training is the stimulus; protein supports it; total calories and consistency over months do the heavy lifting. As ever in this section: the training does most of the work.

The group that actually under-eats: older adults

Here is the part of the protein story that deserves far more attention than it gets. From around midlife, we gradually lose muscle mass and strength — a process called sarcopenia — and it accelerates with age. It's not cosmetic: muscle is what lets an older person rise from a chair, climb stairs, recover from an illness without ending up bed-bound, and stay out of the cascade that begins with a fall.

Two things make this worse together. Ageing muscle is less responsive to protein — it takes a bigger dose to trigger the same muscle-building signal — and older adults often eat less of it, through smaller appetites, dental problems, or meals that drift towards tea and toast. Much expert opinion suggests older adults benefit from intakes above the standard reference figure, often cited around 1.0 to 1.2 grams per kilogram, combined — crucially — with resistance exercise, because protein without the stimulus of using muscles does little. The young man weighing his chicken is over-attending to a problem he doesn't have. His grandmother has the real one, and no one's told her.

There's a third group worth flagging briefly: people losing weight rapidly, including on GLP-1 medicines. Fast weight loss strips away some muscle alongside fat, and adequate protein plus resistance training helps protect lean mass during it — a general principle, not a personalised plan, and one to raise with whoever is overseeing the treatment.

Distribution, food first, and the powder question

Two practical points cut through most of the noise. First, spreading protein across the day — a decent amount at each meal rather than a tiny breakfast and a huge dinner — appears to use it more efficiently for muscle than loading it all at night. For the under-eating older adult, simply getting some protein at breakfast can be the single most useful change.

Second, food first. Whole foods — eggs, dairy, fish, meat, beans, lentils, tofu — bring protein wrapped in other nutrients, and most people can hit even athletic targets from food alone. Powders aren't magic and they aren't poison; they're convenience. A scoop is a fast, portable way to top up when a meal isn't practical, no better gram-for-gram than chicken, and worth buying boring and third-party tested rather than for the adjectives on the tub.

The kidney myth

The most persistent worry about higher protein is that it harms the kidneys, and it deserves a clear answer. In people with healthy kidneys, there is no good evidence that higher intakes within the ranges discussed here cause kidney damage. The myth comes from a real fact misapplied: people who already have significant kidney disease are often advised to moderate protein, and that specific recommendation got generalised into a universal warning. If you have kidney disease, protein intake is a genuine conversation for your own clinician. If you don't, the kidney fear is largely misplaced.

Practical takeaways

• The UK reference figure (~0.75 g/kg/day) is a floor to prevent deficiency, not a target for thriving — most people clear it easily.
• Regular resistance training justifies more — roughly 1.4–2.0 g/kg/day — but there's a ceiling, and training and total calories matter more than chasing the exact gram.
• Older adults are the group genuinely at risk of under-eating protein; higher intakes plus resistance exercise help protect the muscle that keeps them independent.
• Spread protein across meals, get it from food first, and treat powders as convenient top-ups rather than anything special.
• In healthy kidneys, the "protein wrecks your kidneys" claim is not supported; it's a misapplied caution from kidney-disease guidance.

What this doesn't mean

It doesn't mean everyone should chase high-protein targets, or that eating more protein will, by itself, build muscle without the training to drive it. And "safe for healthy adults" is not the same as "right for you" — kidney disease, certain metabolic conditions, and some medications change the picture, which is exactly why blanket internet targets aren't personal advice.

When to seek medical advice

Speak to your GP or a registered dietitian before significantly changing your protein intake if you have kidney disease, diabetes, or another chronic condition, or if you're an older adult losing weight or strength unexpectedly — unintentional weight loss in later life is worth a proper look. If you're losing weight rapidly, on medication or otherwise, raise muscle preservation with the clinician overseeing it rather than improvising.

A closing thought

Protein anxiety, like most nutrition anxiety, has been sold to the people who least need it and withheld from the people who most do. The fix for the gym-goer is usually "relax, you're fine." The fix for his grandmother might genuinely change how the next decade of her life goes. If protein advice ever reaches the right person, that's the one to reach.

Further reading and sources

• Scientific Advisory Committee on Nutrition (SACN) — dietary reference values for protein
• British Dietetic Association — food fact sheets on protein and healthy eating
• International Society of Sports Nutrition — position stand on protein and exercise
• Peer-reviewed reviews on protein intake, sarcopenia and resistance training in older adults
• NHS — Eat Well: protein and a balanced diet