Why You Need More Protein After 40 (Even If You're Not Trying to Build Muscle)

Most people don't notice themselves getting weaker. It's too gradual for that. You just clock, somewhere in your late 40s or 50s, that the shopping feels heavier than it used to, or that you're blowing a bit harder at the top of the station steps. The body's doing slightly less than it did a decade ago and you couldn't say exactly when that started.

Protein is one of the cheapest ways to slow that down. It's got nothing to do with wanting to look a certain way, and you don't need to be a bodybuilder for it to matter. Muscle is what keeps you mobile, steady on your feet and independent as you get older, and this isn't a story about being deficient in it.

The difference between scraping by and staying strong

The official UK recommendation for protein is 0.75 g per kilo of bodyweight a day. For someone who's 75 kg that's about 56 g, and most people over 40 clear it without thinking.

That number was never meant to keep you strong into old age. It's the floor, the amount that stops most of the population developing an outright deficiency. Preserving muscle, strength and physical function as you age is a completely different job, and the gap between those two jobs is what this whole thing turns on.

The groups who actually study ageing muscle land somewhere higher. The clinical nutrition and geriatric bodies, ESPEN, PROT-AGE, the sports nutrition societies, tend to settle around 1.0 to 1.2 g/kg a day for healthy older adults, going up to 1.2 to 1.5 for anyone ill, recovering, frail or training hard. For that same 75 kg person you're now talking about 90 g a day rather than 56.

None of that means you have to double your intake or chase 1.6 g/kg like a competitive lifter. It means the minimum keeps you adequate and not much more, and if what you care about is protecting ageing muscle, it's the wrong number to be aiming at.

The UK data makes the point better than I can. In the government's own review, average protein intake in the over-65s cleared the minimum comfortably, and yet 27% of 65-to-74-year-olds, and a third of the over-75s, were still under 0.75 g/kg/day. The average reads fine while a big slice of people quietly fall through it.

Muscle is the tissue you can't afford to lose

From your mid-40s on, muscle mass and quality start to slide, and strength drops faster than mass does. That's the part worth sitting with. You can be losing real capability quicker than the mirror lets on.

It isn't a cosmetic problem either. Skeletal muscle is the main place your body clears glucose out of the blood, so it's central to your metabolic health, not just to hauling things about. Low strength and low muscle mass track with more falls, more fractures, more time in hospital, more trouble with everyday tasks, and, in the case of something as basic as grip strength, a shorter life. It's protective tissue. Let it waste and the fallout reaches a long way past how you fill a shirt.

I'll be straight about what that evidence actually is. Most of it is observational, so it shows muscle is a powerful marker of how well people age rather than proving protein on its own fixes any single outcome. But the direction of travel is consistent, and hanging onto your muscle is about as safe a long-term bet as health offers. It's the sort of slow, compounding return that tends to land with the people I work with, a lot of them running businesses or commuting into London with next to no spare time, once you frame it in decades rather than weeks. That's the thinking behind my PrimeFit approach and while it's unglamorous the payoff is worth it.

"I'm not a bodybuilder, and I already eat plenty"

Fair enough. If you're having chicken with your dinner most nights, you probably are getting a reasonable amount in. The trouble usually isn't how much. It's when.

Most people pile nearly all their protein into the evening meal. Breakfast is almost always the lowest-protein meal of the day, toast, cereal, a coffee grabbed on the way to the train, and lunch often isn't much better. So you spend the first two-thirds of the day barely touching the signal that tells your muscles to repair and rebuild.

That matters more as you age, because of something called anabolic resistance. In plain terms, older muscle needs a louder signal than younger muscle to switch protein-building on. The classic study on this found younger men maxed out their response at around 0.24 g/kg of protein per meal, while older men needed close to double, roughly 0.40 g/kg, to get the same effect. A separate trial showed that after a full-body workout, 40 g of protein beat 20 g for switching that response on at all.

What you're actually aiming for is somewhere between 25 and 40 g of protein in each meal, spread through the day, instead of one big hit at night. For most people that means sorting out breakfast and lunch rather than making dinner any bigger. It's the most common gap I see, people come into the gym at Lightwater having eaten next to no protein before mid-afternoon, and fixing it costs nothing but a bit of forethought.

A few myths worth clearing up

The kidney one comes up constantly. "High protein wrecks your kidneys" doesn't survive contact with the evidence, at least not for healthy people. Meta-analyses of controlled trials show no harm to kidney function from higher-protein diets. Filtration rate can rise a touch, but that's the kidney adapting to the extra workload, the same way your heart rate climbs when you take the stairs. It isn't damage. The real exception is if you've been diagnosed with chronic kidney disease, where the advice genuinely is different and you should follow it, the guidance there usually keeps protein lower. Safe for healthy kidneys and safe for everyone aren't the same statement.

Then there's the idea that plant protein doesn't count, which is overstated. Gram for gram, a lot of plant proteins are absorbed slightly less efficiently and carry less leucine, the amino acid that helps flip the muscle-building switch. But soy holds its own against dairy over the long run, and a well-planned plant-based diet hits muscle-supportive targets perfectly well. It just takes more thought about portions and staples than slapping a chicken breast on a plate.

And the big one, that a large protein dinner covers you for the whole day. Your daily total does matter most, and I won't oversell the perfect-distribution idea, because the long-term trials on it are genuinely mixed. But repeatedly nudging muscle protein synthesis across the day beats doing it once at eight in the evening, especially as you get older. Get a proper protein source into each meal, breakfast and lunch included. That's the version the evidence actually supports, not "you must eat exactly 30 g every three hours."

What to actually do about it

The plan is short.

Get somewhere between 25 and 40 g of protein into each main meal, scaled to your size and appetite, and put the effort into the meals you're currently skimping on, usually breakfast and lunch. Build it from whole food first: eggs, Greek yoghurt, dairy, fish, lean meat, and for plant-based eaters, soy, beans, lentils and the higher-protein staples. A shake has its place on a rushed morning or when your appetite's gone, but it's a convenience and nothing more.

Then there's the part protein can't do on its own. Eating more of it hands your body the raw material, but it won't build or hold muscle unless you're loading that muscle with resistance training. The research is consistent here, protein alongside strength work reliably protects and builds muscle, while extra protein by itself does very little, particularly in people who are already reasonably well fed. The NHS recommends strength work for all the major muscle groups at least twice a week, and that lines up with the physiology exactly. Eat all the protein you like, but if you aren't lifting heavy things, your body won't give it a job to do.

That's the honest end of it, and it's also where most people get stuck. Knowing you should lift a couple of times a week and eat more protein is the easy bit. Fitting progressive strength training around a full week, a commute, a business, the kids, the lot, so that you're still doing it in six months is where it tends to fall apart. That's the job PrimeFit is built for: turning the vague intention into a structured, efficient routine that earns its keep from the two or three sessions a week you can realistically give it.

If you'd like a hand with it, come and book a diagnostic consultation with me at Lightwater Leisure Centre. We'll take an honest look at where your strength and your nutrition actually sit, and build you something you'll still be doing years from now. Start at edefitness.com, or email me straight on [email protected].

Rob Ede is a Level 4 nutrition coach and personal trainer running PrimeFit at Lightwater Leisure Centre, working with busy professionals across Lightwater, Bagshot, Windlesham and the wider Surrey Heath area.

References (for the curious)

SACN. Nutrition and older adults living in the community. UK Government, 2021.

ESPEN. Practical guideline: Clinical nutrition and hydration in geriatrics. 2022.

Moore DR, et al. Protein ingestion to stimulate myofibrillar protein synthesis requires greater relative protein intakes in healthy older versus younger men. J Nutr, 2015.

Macnaughton LS, et al. The response of muscle protein synthesis following whole-body resistance exercise is greater following 40 g than 20 g of ingested whey protein. Physiol Rep, 2016.

Nunes EA, et al. Systematic review and meta-analysis of protein intake to support muscle mass and function in healthy adults. J Cachexia Sarcopenia Muscle, 2022.

Kokura Y, et al. Enhanced protein intake on maintaining muscle mass during weight loss in adults with overweight or obesity. 2024.

Devries MC, et al. Changes in kidney function do not differ between healthy adults consuming higher- compared with lower- or normal-protein diets. Am J Clin Nutr, 2018.

Cruz-Jentoft AJ, et al. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing, 2019.

NHS. Physical activity guidelines for adults aged 19 to 64.

Medical disclaimer: This article is for general information and education only and is not a substitute for personalised medical advice, diagnosis or treatment. I am a qualified personal trainer and nutrition coach, not a doctor. Always consult an appropriate healthcare professional before making significant changes to your exercise, nutrition or medication, particularly if you have a medical condition, are pregnant, or take prescription medication.

Copyright © 2026 Rob Ede. You may quote brief excerpts from this article provided you include appropriate attribution and a link to the original. Please do not reproduce or republish the article in full without written permission.