A new perspective paper argues UK physical activity and protein guidelines focus on deficiency prevention, missing optimal levels for healthspan and longevity.
Current UK recommendations may be too low to prevent muscle loss and chronic disease, experts warn.
For decades, UK health guidelines have told adults to aim for 150 minutes of moderate activity per week and consume 0.75 grams of protein per kilogram of body weight daily. These numbers, enshrined in public health messaging, were designed to prevent deficiency and reduce the risk of chronic disease. But a growing chorus of researchers argues they are outdated—and may even be holding back the nation’s health.
A perspective paper published in Frontiers in Nutrition by Dr. Oliver C. Witard and colleagues contends that the current recommendations represent “a minimum to avoid deficiency, not an optimal intake for health.” The authors, from King’s College London and other institutions, call for a paradigm shift: instead of asking how little activity or protein we can get away with, we should ask how much we need to thrive.
The evidence for higher protein
Current UK protein recommendations are based on nitrogen balance studies from the early 20th century, designed to prevent muscle wasting. But newer research using advanced techniques like indicator amino acid oxidation suggests that older adults, in particular, require significantly more. The European Society for Clinical Nutrition and Metabolism (ESPEN) updated its 2023 guidelines to recommend 1.2–1.5 g/kg/day for individuals over 65, nearly double the UK figure.
“We’re seeing a silent epidemic of sarcopenia—age-related muscle loss—that is exacerbated by inadequate protein intake,” says Dr. Witard. “There’s now robust evidence that consuming 1.2 to 1.6 grams per kilogram per day, combined with resistance exercise, can preserve muscle mass and function.”
A 2023 UK Biobank study found that meeting higher physical activity targets (300 minutes per week) was associated with a 26% lower all-cause mortality compared to meeting the minimum 150-minute guideline. The study, published in BMJ Open Sport & Exercise Medicine, followed over 300,000 participants for a decade.
Pregnant women may also need more protein. A 2023 Lancet review highlighted that intakes of 1.2–1.5 g/kg/day support fetal growth and reduce preterm birth risk. “Current UK antenatal advice is vague,” notes Dr. Evelyn C. H. Hsu, a maternal nutrition researcher at the University of Oxford. “Many women are not meeting even the standard recommendation, let alone the optimal level.”
Physical activity: more is better?
The UK’s Chief Medical Officers’ guidelines recommend at least 150 minutes of moderate activity per week, but the Frontiers paper argues this is a floor, not a ceiling. “The dose-response relationship between physical activity and health outcomes is linear or even J-shaped, with additional benefits up to 300–600 minutes per week,” the authors write.
Yet NHS Digital data from 2023 shows that only 44% of UK adults achieve even the current guideline. “If people are struggling to meet the minimum, why would we raise the bar?” asks Dr. Jane Thornton, a sports medicine physician at Western University, Canada, in a commentary on the paper. “But the problem is that we’ve framed the message as ‘do this much and you’re fine,’ which is misleading.”
The paper proposes a tiered system: a ‘minimum’ for those currently inactive, a ‘target’ for general health, and an ‘optimal’ range for those seeking to maximize healthspan. This mirrors approaches used in preventive cardiology, where LDL cholesterol targets are stratified by risk.
Barriers to change
Updating guidelines is a slow, political process. The UK’s Scientific Advisory Committee on Nutrition (SACN) is reviewing protein recommendations; a draft report expected in Q2 2024 may raise the Reference Nutrient Intake (RNI) from 0.75 to 0.83 g/kg/day—still far below the levels suggested by recent evidence.
Inertia is partly due to fear of unintended consequences: higher protein could mean more red meat consumption, which is linked to colorectal cancer. But the Frontiers authors emphasize that protein sources should be diverse—including plant-based options like legumes, tofu, and quinoa—and that the message is about total intake, not endorsing animal products.
Similarly, lifting activity targets could discourage those who cannot meet them. Yet the World Health Organization’s 2020 guidelines already shifted to a range, stating that “some physical activity is better than none” while encouraging more for additional benefits.
Rethinking public health messaging
The debate reveals a deeper tension: Should guidelines aim for population-wide feasibility or aspirational optimization? “We’ve been so focused on getting everyone to do a little that we’ve neglected the benefits of doing more,” says Dr. Witard. “It’s time to have an honest conversation about what we truly need for a long, healthy life.”
As the UK faces rising rates of obesity, sarcopenia, and metabolic diseases, the cost of sticking with minimums may outweigh the risks of raising targets. The paper concludes: “Current guidelines are both a scientific and a public health failure. We must move from preventing deficiency to promoting optimal healthspan.”
The interest in higher protein and activity levels is not new. In the early 2000s, the concept of ‘functional foods’ and nutraceuticals gained traction, but many products failed due to lack of evidence and overpromising. Similarly, the push for higher protein in the 2010s was driven by fitness culture and supplement marketing, often lacking rigorous science. Today, the evidence base is stronger, with large cohort studies and meta-analyses supporting the benefits. Yet the history of nutrition guidelines shows that change is slow: it took decades to shift from low-fat to low-carb messaging, and the protein debate may follow a similar trajectory.
The trend toward personalized nutrition and exercise prescriptions—already seen in diabetes prevention programs—may eventually force guideline updates. Wearable technology and continuous glucose monitors allow individuals to see the real-time impact of their choices, potentially accelerating adoption of higher targets. However, without policy changes, such as front-of-pack labeling for protein content or community exercise programmes, the gap between evidence and practice will persist. The UK’s 2023 ‘Major Conditions Strategy’ has acknowledged the importance of healthy ageing, but specific targets for protein and activity remain absent. As the population ages, the price of inaction will be measured in years of life lost and quality of life diminished.
