How Much Protein Do You Need After 40?

1. Has the official protein advice changed?

In the US, yes. On 7 January 2026 the American health authorities published the 2025–2030 Dietary Guidelines. For the first time they set an explicit daily target in grams per kilogram: 1.2 to 1.6 g per kg of body weight. The previous reference, 0.8 g per kg, had stood for decades.

The new figure is not settled science. It was derived mainly from weight-management trials, and a 2026 perspective in the Journal of Nutrition questions whether one higher target should apply to everyone. But the direction of travel is clear, and it points up.

UK guidance has not moved. The British Nutrition Foundation still lists the reference intake at 0.75 g per kg a day. That works out at roughly 56 g for an average man and 45 g for an average woman.

For older adults, European experts split the difference years ago. The PROT-AGE study group, appointed by the European geriatric medicine society, reviewed the evidence on ageing muscle.

“To help older (>65 years) people maintain and regain lean body mass and function, the PROT-AGE study group recommends average daily intake at least in the range of 1.0 to 1.2 g protein per kilogram of body weight per day.”

— PROT-AGE Study Group position paper, Journal of the American Medical Directors Association

So the honest summary is a range, not a rule. Somewhere between 1.0 and 1.2 g per kg is where expert advice for mid-life and older adults now clusters, with the new US guidance sitting higher still.

2. Why do you need more protein after 40?

Because your muscle stops listening as closely. Researchers call it anabolic resistance. The same portion of protein triggers less muscle-building in a 55-year-old than in a 25-year-old, so the same diet quietly delivers less.

The background trend is steady. A review in Current Opinion in Clinical Nutrition puts muscle loss at 3 to 8% per decade from age 30, and faster after 60. Protein contributes to the maintenance of muscle mass, which is why the recommendations rise as you age rather than fall.

Activity moves the target too. PROT-AGE advises 1.2 g per kg or more for older adults who exercise regularly, and 1.2 to 1.5 g per kg during acute or chronic illness, under medical guidance.

Protein matters most when you are losing weight, because rapid weight loss takes some lean tissue with it. That is one reason protein targets feature in GLP-1 clinics. If you are on that path, our guide to blood tests on GLP-1 medication covers the markers worth tracking.

3. How much protein is that in real food?

Take your weight in kilograms and multiply by 1.0 and 1.2. That is your working range.

Spread matters as much as total. PROT-AGE suggests 25 to 30 g of protein per meal for older adults, because a single large evening dose does less for muscle than three decent servings.

Powders can close the gap, and whey is a reasonable tool rather than a requirement. One caveat: taken close to a blood draw, it can nudge some results. Our guide to whey protein and blood tests explains which markers move.

4. Can more protein harm your kidneys?

For healthy kidneys, the expert answer is reassuring. The PROT-AGE review found no reason for healthy older adults to restrict protein.

The exception is real, though. PROT-AGE advises that older people with severe kidney disease, an eGFR below 30, who are not on dialysis, may need to limit their intake. eGFR is the estimated glomerular filtration rate, a standard blood measure of how well your kidneys filter.

Here is the practical problem. Early kidney trouble usually has no symptoms, so you cannot feel which group you are in. The only way to know your eGFR is to measure it. Our guide to the kidney function test explains the panel of markers behind it.

One more number worth knowing: urea. It is a waste product of protein breakdown, and it commonly sits higher on a high-protein diet. Seeing your baseline first makes any later change readable rather than alarming.

5. Which markers should you check before you change your diet?

Five markers cover the protein question. Creatinine, urea and eGFR show how your kidneys are handling the load. Albumin and total protein are the main proteins circulating in your blood. They are not a meter of how much you ate this week, but they complete the baseline picture.

Our Thyroid & Vital Organs panel (£159) measures all five alongside thyroid, liver and full cholesterol markers, 16 in total, from one home finger-prick sample. Test before you change your intake, then again a few months after, and you can see the effect rather than guess at it.

Two honest caveats. If you take creatine, your creatinine can read high without anything being wrong with your kidneys. Our guide to creatine and creatinine covers it. And if muscle loss is the reason you are reading this, our sarcopenia blood tests guide maps the wider set, from vitamin D to inflammation.

A blood test measures these markers. It does not diagnose anything, and a result that concerns you belongs with your GP. For the wider picture on flagging energy, start at the energy and fatigue hub.

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