How much protein you need as you age — and why the old advice was too low

The official number is 0.8 grams of protein per kilogram of body weight per day. It appears on government guidance in the UK, the US and most of Europe, it is identical for a 25-year-old and an 80-year-old, and a substantial body of research now suggests it is too low for the older half of that range.

This is not a fringe position. It is the stated view of the PROT-AGE study group, of the ESPEN expert group, and of a long line of researchers who have been arguing it since the early 2010s.

Understanding why matters, because protein is the one nutritional lever that connects directly to the thing that determines independence in later life: how much muscle you keep.

Where 0.8 came from

The figure derives from nitrogen balance studies — a method that measures how much nitrogen goes in as protein against how much comes out, and identifies the intake at which the two match.

Two problems with using that number for a 70-year-old.

Balance is not the same as optimal. Nitrogen balance identifies the point at which you stop losing protein. It says nothing about the intake that best preserves muscle, function or strength. It is a floor, and it has been treated as a target.

The studies were mostly in young adults. The meta-analysis underpinning the current recommendation drew on nitrogen balance data of which very few came from older individuals. The one-size-fits-all figure does not account for age-related changes in metabolism, inflammation or hormonal status.

When newer methods are applied, the number moves. Studies using the indicator amino acid oxidation technique estimated the requirement in older adults at roughly 1.2 g/kg/day — about 40% above the current recommendation.

Anabolic resistance

The physiological reason older adults need more is that they get less out of what they eat.

Muscle protein synthesis is triggered when amino acids — particularly leucine — reach the muscle and activate a signalling pathway. In older adults, that response is blunted for a given dose. Estimates put the reduction at roughly 16–30% compared with younger adults at matched intake.

Three things compound it. Baseline muscle breakdown is elevated in older muscle, partly through low-grade chronic inflammation. Appetite tends to fall, and protein is the macronutrient most often displaced when total intake drops. And reduced physical activity worsens the resistance directly.

That last point is the encouraging one. Anabolic resistance is not a fixed consequence of age. When older men performed resistance exercise before consuming protein, the anabolic response approached the levels seen in younger men. One group of researchers described it as a dimmer switch rather than an on-off state — modulated by habitual activity, body composition and inflammation.

Which means the intervention here is not protein alone. It is protein plus loading. Either one on its own delivers a fraction of the result.

The numbers worth using

Expert groups converge on a range rather than a figure.

PROT-AGE recommends at least 1.0 to 1.2 g/kg/day for healthy older adults, rising to 1.2–1.5 g/kg/day for those with acute or chronic illness. ESPEN lands in the same territory. A broader review of protein requirements beyond the RDA proposes 1.2–1.6 g/kg/day as a more appropriate target for adults generally.

For a 70 kg person, the practical difference is stark: 56 g a day under the official recommendation, versus 84–105 g under the expert consensus.

The per-meal threshold matters as much as the daily total. Because of anabolic resistance, older adults need a larger dose in a single sitting to trigger muscle protein synthesis — PROT-AGE puts the threshold at roughly 25–30 g of protein per meal, containing about 2.5–2.8 g of leucine.

This is where most people’s intake fails, and it fails in a predictable place. A typical day loads almost all its protein into the evening meal: toast for breakfast, a sandwich at lunch, then 50 g of protein at dinner. Three meals, one of which clears the threshold.

Spreading the same total across three or four meals of 25–30 g each does more with identical food.

What that looks like on a plate

Roughly 25–30 g of protein is:

• 100–120 g of cooked chicken, fish or lean meat
• 4 large eggs
• 170 g of Greek yoghurt plus a handful of nuts
• 150 g of cooked lentils plus a slice of wholegrain bread
• 200 g of firm tofu
• 30 g of whey or soy protein powder

Breakfast is the meal where the shortfall is nearly universal in Western diets. Cereal, toast or fruit typically delivers under 10 g. Fixing breakfast alone often moves someone from clearly inadequate to broadly adequate.

Plant sources work, with one adjustment: most are lower in leucine, so plant-based eaters generally need somewhat higher totals and benefit from combining sources. Soy, lentils, and pulses combined with grains do the job.

What the evidence supports, and what it does not

Higher protein intake is not straightforwardly better in all circumstances, and the honest picture has a caveat that gets omitted from most coverage.

Randomised feeding trials indicate that intakes above the RDA — averaging around 1.3 g/kg/day — do not by themselves change lean body mass or physical function under ordinary, non-stressed conditions. Where they do help is in the presence of a stressor: energy restriction, or resistance training.

The observational evidence is more encouraging. In a three-year study of 2,066 people aged 70–79, participants in the highest quintile of protein intake — around 1.1 g/kg/day — lost 40% less lean mass than those in the lowest quintile, at around 0.7 g/kg/day.

Putting those together: protein is permissive rather than active. It does not build muscle on its own. It removes the constraint that stops training from building muscle, and it slows loss during the periods when loss is happening.

Safety, and the kidney question

The concern people raise most often is kidney damage, and the evidence does not support it in healthy people. Higher protein intakes within the ranges above have not been shown to impair kidney function in adults with normal kidneys.

If you have existing kidney disease, this is different and specific to you. Protein restriction is sometimes part of managing chronic kidney disease, and the target has to come from the clinician managing it, not from an article.

The other practical constraint is that protein is satiating. For an older adult already struggling to eat enough, pushing protein higher can displace total calories and make matters worse. In that situation the priority is total intake first.

The connection worth holding onto

Muscle is not decoration. Grip strength predicts mortality better than blood pressure; muscle mass and strength determine whether you can rise from a chair unaided at eighty; and the decline begins decades before anyone notices it.

Protein and resistance training are the two inputs that change that trajectory, and neither works properly without the other. The official protein recommendation was designed to prevent deficiency in a young population, and it has been quietly repurposed as a target for a population it was never studied in.

Aiming higher — 1.2 g/kg or above, spread across the day — costs nothing beyond attention, and is one of the few dietary changes with a clear mechanism connecting it to how the last decades of your life actually go.

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This article is for general information and is not medical advice. If you have kidney disease, liver disease, or any condition affecting how you process protein, speak to your doctor before increasing intake.

Sources

1. Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. Journal of the American Medical Directors Association, 2013;14(8):542–559. https://www.sciencedirect.com/science/article/pii/S1525861013003265
2. Phillips SM, Chevalier S, Leidy HJ. Protein “requirements” beyond the RDA: implications for optimizing health. Applied Physiology, Nutrition, and Metabolism, 2016;41(5):565–572. https://cdnsciencepub.com/doi/10.1139/apnm-2015-0550
3. Deutz NE, Bauer JM, Barazzoni R, et al. Protein intake and exercise for optimal muscle function with aging: recommendations from the ESPEN Expert Group. Clinical Nutrition, 2014;33(6):929–936.
4. Nutritional interventions: dietary protein needs and influences on skeletal muscle of older adults. The Journals of Gerontology: Series A, 2023. https://academic.oup.com/biomedgerontology/article/78/Supplement_1/67/7199271
5. Protein requirements during aging: indicator amino acid oxidation estimates. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4997405/