Dharani Yerrakalva is a GP and an academic researcher in primary care with a special interest in preventative medicine.
As glucagon-like peptide-1 (GLP-1) receptor agonists become embedded within obesity care, a striking paradox is emerging. We are investing unprecedented energy, resources, and attention into pharmaceutical treatment of obesity at the very moment that one of the most important determinants of long-term health — physical activity — risks becoming an afterthought.
As a GP, I increasingly see patients who have started GLP-1 treatment through private providers before presenting to NHS primary care for ongoing support. Some have achieved substantial weight loss. What is often less clear is how physical activity fits into their treatment plan. Many report receiving little specific advice. Others assume that because the medication is working, exercise is no longer necessary.
“… much of the public narrative surrounding GLP-1 drugs focuses on kilograms lost rather than health gained.”
This matters because obesity management has never been solely about weight loss. Yet much of the public narrative surrounding GLP-1 drugs focuses on kilograms lost rather than health gained. In doing so, we risk reinforcing a longstanding misconception: that the primary purpose of physical activity is to reduce body weight.
The rapid expansion of GLP-1 use makes this concern increasingly relevant. A recent population study estimated that approximately 1.6 million adults in Great Britain used GLP-1 medications for weight loss between 2024 and 2025, the vast majority through private providers.1 NHS England has estimated that up to 3.4 million adults could eventually become eligible for treatment as access expands.2 The scale of this transformation should prompt an important question. What kind of obesity treatment system are we building?
Beyond weight loss
The success of GLP-1 receptor agonists is undeniable. For many patients, these medications achieve levels of weight reduction previously seen only with bariatric surgery. They represent a major therapeutic advance and have transformed possibilities for obesity treatment. Yet weight loss is only one component of preventative health.
Physical activity improves cardiovascular fitness, physical functioning, mental wellbeing, and mortality risk independent of body weight.3 Individuals who are physically active but living with obesity can have better health outcomes than those with lower body weight who remain inactive. The health benefits of movement extend far beyond calorie expenditure.
Ironically, maintaining physical activity may become even more important during GLP-1 treatment. Weight loss achieved with these drugs includes reductions in both fat mass and lean mass. Current evidence suggests that between one-quarter and two-fifths of total weight lost may come from fat-free mass.4,5 Preserving muscle strength and physical function therefore becomes an important clinical objective, particularly among older adults and those likely to remain on treatment for prolonged periods.
Physical activity also appears central to long-term weight maintenance. Evidence consistently demonstrates that higher levels of activity are associated with reduced weight regain following weight loss.6,7 This is especially relevant given growing evidence that weight regain after discontinuation of GLP-1 treatment is common and may occur rapidly.8,9
“… healthcare systems are structured far more effectively around prescribing medication than supporting behaviour change.”
If physical activity contributes to preserving muscle mass, maintaining function, improving cardiovascular health, and sustaining weight loss, then it should not be regarded as an optional adjunct to pharmacotherapy. It should be viewed as a core component of treatment.
The implementation gap
The difficulty is that healthcare systems are structured far more effectively around prescribing medication than supporting behaviour change.
National Institute for Health and Care Excellence guidance recommends that pharmacological treatment for obesity should be delivered alongside lifestyle interventions, including physical activity support.10 In principle, this reflects a comprehensive model of care. In practice, the infrastructure required to deliver such support at scale is often absent.
Exercise referral schemes remain variable in availability and quality. Community-based prevention services are fragmented and unevenly distributed. Opportunities for sustained physical activity support frequently depend on local commissioning arrangements, creating substantial geographical variation in provision.
Meanwhile, general practice is expected to bridge the gap. This expectation sits uneasily alongside current realities. Consultation time is finite, workforce pressures are considerable, and preventive care competes with growing clinical complexity. Johansson and colleagues have argued that implementing preventive recommendations alone may consume a substantial proportion of available clinical time.11 Yet obesity strategies continue to assume that behavioural support can simply be absorbed into routine care.
The result is a familiar pattern. We create evidence-based guidance recommending physical activity interventions without creating the infrastructure required to deliver them.
A pharmaceutical model of obesity care
“GLP-1 receptor agonists are changing not only how obesity is treated but also how obesity is understood.”
There is a broader issue here. GLP-1 receptor agonists are changing not only how obesity is treated but also how obesity is understood.
Historically, obesity management has often been criticised for placing excessive responsibility on individuals while ignoring biological and environmental drivers of weight gain. The emergence of highly effective medications represents an important correction to this narrative. However, there is a risk of overcorrection. If obesity becomes framed predominantly as a condition managed through medication, physical activity may gradually lose prominence within both clinical conversations and public understanding. The danger is not that patients will stop losing weight. The danger is that obesity care becomes increasingly focused on weight itself while neglecting the broader behaviours that support lifelong health.
This challenge is particularly relevant given the current dominance of private-sector prescribing. While some providers offer comprehensive support, the quality and intensity of lifestyle interventions accompanying treatment appears to be highly variable. As increasing numbers of patients transition into NHS care, primary care clinicians may find themselves managing the downstream consequences of treatment pathways over which they had little influence.
Rebalancing the system
If physical activity is genuinely considered an essential component of obesity care, then it requires investment equivalent to the attention currently directed towards medication. That means expanding community-based prevention services, strengthening links between healthcare and physical activity programmes, embedding exercise support within obesity pathways, and ensuring that providers initiating treatment remain accountable for delivering holistic care. Otherwise, we risk creating a healthcare system that excels at generating weight loss but struggles to support long-term health.
The question facing primary care is not whether GLP-1 receptor agonists work. The more important question is whether we are prepared to invest in the systems that allow patients to realise their full benefits. If we are not, physical activity may become the forgotten casualty of the GLP-1 revolution.
References
1. Jackson SE, Brown J, Llewellyn C, et al. Prevalence of use and interest in using glucagon-like peptide-1 receptor agonists for weight loss: a population study in Great Britain. BMC Med 2026; 24(1): 1.
2. NHS England. Interim commissioning guidance. 2026. https://www.england.nhs.uk/long-read/interim-commissioning-guidance-nice-ta1026-tirzepatide (accessed 3 Sep 2026).
3. Koolhaas CM, Dhana K, Schoufour JD, et al. Impact of physical activity on the association of overweight and obesity with cardiovascular disease: the Rotterdam Study. Eur J Prev Cardiol 2017; 24(9): 934–941.
4. Ceasovschih A, Asaftei A, Lupo MG, et al. Glucagon-like peptide-1 receptor agonists and muscle mass effects. Pharmacol Res 2025; 220: 107927.
5. Conte C, Hall KD, Klein S. Is weight loss-induced muscle mass loss clinically relevant? JAMA 2024; 332(1): 9–10.
6. Kerns JC, Guo J, Fothergill E, et al. Increased physical activity associated with less weight regain six years after “The Biggest Loser” competition. Obesity (Silver Spring) 2017; 25(11): 1838–1843.
7. Saadeddine D, Foglia M, Berri E, et al. Daily steps during nutritional lifestyle modification programs for obesity management: a systematic review and meta-analysis. Int J Environ Res Public Health 2026; 23(4): 522.
8. West S, Scragg J, Aveyard P, et al. Weight regain after cessation of medication for weight management: systematic review and meta-analysis. BMJ 2026; 392: e085304.
9. Budini B, Luo S, Tam M, et al. Trajectory of weight regain after cessation of GLP-1 receptor agonists: a systematic review and nonlinear meta-regression. EClinicalMedicine 2026; 93: 103796.
10. National Institute for Health and Care Excellence (NICE). Overweight and obesity management. NG246. London: NICE, 2026. https://www.nice.org.uk/guidance/ng246 (accessed 3 Sep 2026).
11. Johansson M, Guyatt G, Montori V. Guidelines should consider clinicians’ time needed to treat. BMJ 2023; 380: e072953.
Featured photo by Fitsum Admasu on Unsplash.
