Protein recommendations are a source of persistent confusion, partly because two different questions get answered with the same number.

The official recommended intake in most countries sits around 0.8 grams per kilogram of body weight per day. That figure is widely quoted and widely misunderstood.

What the official figure means

It's derived from nitrogen balance studies and represents the amount sufficient to meet the requirements of the large majority of healthy adults — essentially, the intake below which deficiency becomes likely.

It is a minimum to prevent inadequacy, not an optimum for any particular outcome. Those are different questions and conflating them is the source of most of the argument.

For a sedentary adult with no specific goals, that intake is genuinely adequate. Most people in high-income countries exceed it without trying.

Where more appears useful

Several situations have reasonable evidence for higher intakes.

Resistance training. Meta-analyses of protein supplementation alongside resistance training have found benefits to strength and lean mass gains up to intakes considerably above the official figure — commonly cited as somewhere around 1.6 grams per kilogram, with limited additional benefit beyond that in most studies.

Older adults. This is possibly the most important and least acted upon. Older adults show anabolic resistance — a blunted muscle protein synthesis response to a given protein dose. Several expert groups have recommended intakes above the general figure for people over about 65, on the reasoning that maintaining muscle mass is central to preserving independence.

Age-related muscle loss is a major contributor to falls, frailty and loss of function, and it's substantially modifiable through resistance exercise and adequate protein together.

During energy restriction. When losing weight, higher protein intake appears to preserve lean mass better and improves satiety. This is one of the more consistent findings in the weight management literature.

Recovery from illness or injury. Requirements rise during catabolic states.

Distribution across the day

An area where the evidence is suggestive rather than settled.

The proposal is that muscle protein synthesis responds to a threshold dose of protein at a meal, and that spreading intake across several meals containing an adequate amount produces a better response than concentrating it in one.

Typical Western eating patterns skew heavily towards protein at the evening meal, with very little at breakfast. Studies comparing even distribution against skewed distribution have found some benefit to evening it out, though effect sizes are modest and not all studies agree.

The practical implication is modest: including a protein source at breakfast is probably worthwhile, particularly for older adults, and it's not a dramatic intervention.

Sources and quality

Protein sources differ in amino acid composition and digestibility, which matters more at lower total intakes.

Animal sources generally provide all essential amino acids in proportions well matched to human requirements, with high digestibility.

Plant sources vary. Individual plant proteins may be lower in one or more essential amino acids — legumes in methionine, cereals in lysine — but a varied plant-based diet across a day readily provides all of them. The older idea that proteins must be combined at each meal has not held up; the body maintains an amino acid pool.

Plant proteins are typically somewhat less digestible, which is one reason recommendations for plant-based diets sometimes suggest slightly higher total intake.

Soy and a few other plant sources have amino acid profiles comparable to animal proteins.

The kidney question

The most common concern raised about higher intakes, and the evidence is reassuring with an important caveat.

In people with healthy kidney function, higher protein intakes have not been shown to cause kidney damage. Reviews examining this consistently find no evidence of harm in healthy individuals at the intakes people actually consume.

The caveat is that in people with existing kidney disease, protein restriction is a standard part of management, and higher intakes are genuinely contraindicated. The recommendation not to increase protein applies to that group and has been generalised inappropriately to everybody.

If you have kidney disease or any condition affecting renal function, this is a conversation with your doctor, not something to decide from general reading.

Supplements versus food

Protein powders are convenient and are not superior to food. The evidence suggests total daily intake matters considerably more than the source.

Where they're genuinely useful: convenience when appetite or time is limited, for older adults struggling to reach adequate intake, and for people with high requirements relative to what they can comfortably eat.

Where they're unnecessary: for most people meeting requirements from ordinary food, which includes most people who buy them.

Food sources bring other nutrients that isolated protein doesn't, which is a reasonable argument for preferring them where practical.

The practical summary

Most sedentary adults meet requirements without effort. If you're training, older, losing weight, or recovering from something, more is likely beneficial, and the intakes with reasonable support are meaningfully above the official minimum.

Spread it across meals rather than concentrating it in one. Prioritise food, use supplements for convenience rather than superiority.

And if you have kidney disease, ignore all of the above and talk to a clinician who knows your specific situation.

This article is general information and is not medical advice. Anyone with a medical condition should discuss dietary changes with a qualified healthcare professional.