Dominic Farsi, Teagasc; King’s College London; Queen’s University Belfast
October 27, 2026
High protein content has become a selling point on foods ranging from breakfast cereals to yoghurts. For anyone hoping to build muscle or stay strong as they age, choosing the product with the most protein can seem sensible. But whether an extra serving will help depends on what they already eat and how they use their muscles.
Someone who regularly lifts weights may benefit from additional protein to support muscle growth. An older person with a small appetite may need help getting enough to maintain strength. Someone already eating enough protein may gain little from adding more.
Understanding those differences can make it easier to decide whether to change your diet, buy a supplement or concentrate on exercise.
Muscle tissue is continually being broken down and rebuilt. Dietary protein supplies amino acids, the small molecules the body uses to make its own proteins, including those in muscle.
Resistance exercise makes muscles work against a load. That load might come from weights or from your own body during an exercise such as press-ups. It stimulates the processes involved in building and repairing muscle, allowing muscles to adapt to repeated demands.
Protein supports this adaptation, but increasing intake does not reproduce the effects of exercise.
A review of 49 trials involving 1,863 participants found that protein supplements produced additional improvements in muscle size and strength during resistance training. Participants were training for at least six weeks. The findings therefore concern protein’s contribution to a training programme, rather than the effects of adding a shake to an otherwise unchanged routine.
For someone already eating enough protein, establishing a manageable strength-training routine may be more useful than searching for another high-protein snack.
More protein does not mean unlimited gains
The UK reference intake for adults is 0.75g of protein per kilogram of body weight each day. For someone weighing 70kg, that is about 53g. This reference intake is intended to cover the needs of most healthy adults, rather than specifically maximise muscle growth.
People undertaking resistance training may benefit from more. In the review of 49 trials, additional protein did not appear to produce further gains in fat-free mass, which includes muscle, once total daily intake reached around 1.6g per kilogram of body weight. For a 70kg adult, that would be about 112g from all food and supplements combined.
That figure is an estimate across studies, rather than a precise threshold for every person. It does not mean everyone needs to aim for it. Existing protein intake and training demands affect whether additional protein is likely to help.
Before buying supplements, consider the protein already supplied by ordinary meals. A supplement may be convenient when food alone does not meet someone’s protein needs. But if their diet already provides enough protein for their activity level, a supplement may offer little extra benefit while increasing costs.
Maintaining muscle with age
Muscle health has consequences well beyond appearance. Losing strength can make getting out of a chair or carrying shopping harder, threatening independence.
Older muscles can become less responsive to the muscle-building effects of a meal, a phenomenon called “anabolic resistance”. This means the same amount of protein may produce a weaker muscle-building response than it does in younger people.
An international expert group recommends around 1.0–1.2g of protein per kilogram daily for healthy adults over 65, alongside exercise. For someone weighing 70kg, that is about 70–84g. Needs can differ during illness, and people with significant kidney disease may require individual advice.
However, preserving muscle involves more than increasing protein. A year-long trial involving 208 healthy older adultsfound that protein supplementation alone did not improve muscle size or strength compared with carbohydrate supplementation. Heavy resistance training combined with whey protein produced benefits that supplementation alone did not.
The practical implication is that advice about protein should also consider opportunities to exercise. Increasing intake without addressing inactivity may leave an important part of muscle maintenance neglected.
Choosing foods that fit your diet
Cottage cheese is one convenient source of protein, but plenty of alternatives are available. Other dairy foods and eggs provide protein, as do beans and soy foods. Preferences and affordability will influence which options someone can eat regularly.
Plant-based diets can also support muscle growth. In a small study of 38 young men, vegans and omnivores followed a 12-week resistance-training programme while consuming similar amounts of protein, approximately 1.6g per kilogram daily. Both groups used supplements to reach that intake. Researchers found similar improvements in muscle mass and strength.
The study was small and involved young men, so it cannot establish that every protein source works equally well in every situation. It does show that muscle gains are possible with an exclusively plant-based diet when protein intake and training are adequate.
For general health, the NHS recommends muscle-strengthening activities on at least two days a week. Exercises should suit someone’s abilities and become progressively more difficult as strength improves.
Someone eating too little protein may benefit from changing their meals. Someone already meeting their needs may make more progress by finding a strength-training routine they can sustain. Those decisions depend on the person’s circumstances, which a protein count on a packet cannot capture.
Whether the goal is lifting a heavier weight or getting up the stairs more easily, the useful question is how eating and activity can support that goal together. Buying more protein is only helpful when it addresses something the person actually needs.
Strange Health is hosted by Katie Edwards and Dan Baumgardt. The executive producer is Gemma Ware, with video and sound editing for this episode by Anouk Millet. Artwork by Alice Mason.
If you’ve got a question about a viral trend or video you’ve seen and you’d like us to delve into the science behind it in a future episode, please email us at strangehealth@theconversation.com.
Listen to Strange Health via any of the apps listed above, download it directly via our RSS feed or find out how else to listen here. A transcript is available via the Apple Podcasts or Spotify apps.
Subscribe to our newsletter.
Dominic Farsi, Marie Skłodowska-Curie Actions (MSCA) Research Fellow, Teagasc; King’s College London; Queen’s University Belfast
This article is republished from The Conversation under a Creative Commons license. Read the original article.
