Key topics:Most people regain lost weight within two years of stopping obesity drugs.Heart, cholesterol, and blood pressure benefits fade after 18 months.Lack of diet guidance risks muscle loss and nutritional deficiencies..Sign up for your early morning brew of the BizNews Insider to keep you up to speed with the content that matters. The newsletter will land in your inbox at 5:30am weekdays. Register here.Support South Africa’s bastion of independent journalism, offering balanced insights on investments, business, and the political economy, by joining BizNews Premium. Register here.If you prefer WhatsApp for updates, sign up to the BizNews channel here..By Michael Peel in London.People who stop taking anti-obesity drugs will within two years return to their original weight and forfeit benefits to the heart, cholesterol levels and blood pressure, according to projections based on a wide-ranging research review.The findings add to evidence of difficulties in sustaining the significant weight loss and associated health advantages many people achieve while they use drugs such as Ozempic, Wegovy and Mounjaro.Experts warn that health authorities need plans to deal with millions of users who will come off the popular medicines during the coming years.“What we’ve shown in this particular piece of analysis is that weight regain after medication is common and is rapid,” said Susan Jebb, a co-author of the research and a public health nutrition scientist at Oxford university.“Obesity is a chronic relapsing condition and it’s very clear that . . . some sort of intervention needs to continue if we’re going to sustain the benefits of these treatments.”Researchers behind the paper published in the BMJ late on Wednesday analysed data from more than 9,000 people from 37 studies that examined the effects of ceasing the drugs. On average, the participants took the medicines for 39 weeks and provided follow-up data for 32. The scientists extrapolated from the studies to forecast what would have happened after a further lapse of time..Read more:. The Economist: It’s not just obesity – drugs like Ozempic will change the world.They found that on average people lost 8.3kg during treatment but were on course to return to their original weight fewer than 21 months after stopping.Beneficial effects on the heart, cholesterol levels and blood pressure for participants who took the medicines were projected to disappear within 18 months.The rates of both weight loss and regain were much faster than for people who took courses focused on changing behaviour.The scientists acknowledged limitations in their work including that almost a third of the trials they surveyed had a high risk of bias. The populations in the drug and behavioural treatment programmes might have differed in potentially important ways, such as the degree of obesity and incidence of comorbidities, they added.Experts not involved in the work said it was consistent with emerging thinking about the medicines’ strengths and limitations.The research highlighted the challenge of maintaining weight loss for the “massive wave of people who will likely be coming off these drugs in the coming months and years”, said Adam Collins, associate professor of nutrition at the University of Surrey.Naveed Sattar, a professor of cardiometabolic medicine at the University of Glasgow, stressed weight loss medicines were “essential” for many people who had very high body mass indices.“This paper cannot yet tell us whether short-term use offers lasting benefits for organs, but it’s plausible that being lighter for even two or three years due to short-term use of the medicines could help slow damage to joints or hearts and kidneys,” Sattar said. Weight-loss drug users may be vulnerable to nutritional deficiencies and muscle loss because they do not receive sufficient guidance on diet, according to a separate paper published in Obesity Reviews on Thursday.Evidence suggests as much as 40 per cent of weight lost using the medicines can be lean body mass, including muscle, said the researchers from the UK’s UCL and the University of Cambridge.The UK National Health Service’s obesity drug treatments include programmes to ensure a balanced diet and increased physical activity. But the vast majority of users buy the medicines privately and often do not receive such support. “If nutritional care is not integrated alongside treatment, there’s a risk of replacing one set of health problems with another, through preventable nutritional deficiencies and largely avoidable loss of muscle mass,” said Marie Spreckley, a Cambridge university scientist who led the research..© 2026 The Financial Times Ltd.