A daily weight loss pill could keep patients slim for life and allow millions to ditch drugs for other diseases, a major trial suggests.
Experts say it can prevent more than 200 conditions linked to obesity and may one day be taken as a preventative measure by people who are only slightly overweight.
The study found users maintained most of their weight loss and associated health gains when switching from jabs such as Wegovy and Mounjaro to the cheaper tablet, named orforglipron.
Researchers believe the pill, which offers a more convenient alternative to weekly injections, is likely to revolutionise the treatment of obesity and slash rates of chronic diseases.
It became available in the United States last month under the brand name Foundayo and is awaiting approval from the UK's Medicines and Healthcare products Regulatory Agency.
It is expected to be approved and available for use in Britain within a year, with hopes its lower cost will allow it to be offered more widely than jabs on the NHS. In the United States, it is sold for around half the price of weight-loss injections.
Two in three adults in the UK are overweight or obese, while the average person prescribed weight-loss injections takes around seven medications for different conditions.
Trials have shown people using fat jabs lose 15 to 20 per cent of their body weight and significantly reduce their risk of major health problems such as heart attacks.
A bottle of Eli Lilly's Foundayo weight-loss pills, along with a single tablet, also known as orforglipron.
However, around two-thirds of the lost weight is typically regained within a year of stopping treatment.
The new research, presented at the European Congress on Obesity, in Istanbul, and published in the journal Nature Medicine, is the first to examine whether switching to pills can maintain those benefits long term.
Researchers found patients who switched to orforglipron maintained far more of their weight loss than those given a placebo.
The trial followed 376 patients who had already lost significant amounts of weight using injectable drugs tirzepatide and semaglutide, sold under brands including Mounjaro and Wegovy, and their weight loss had begun to plateau.
Participants who had used tirzepatide maintained almost 75 per cent of their previous weight loss after switching to the daily pill, compared with 49 per cent for those given placebo.
Among those previously treated with semaglutide, patients maintained almost 80 per cent of their earlier weight loss, compared with 38 per cent on placebo.
Researchers also found improvements in blood pressure, cholesterol and blood sugar control were maintained after patients switched to pills.
Injector pens containing varying size doses of GLP-1 weight-loss drug Wegovy, which contains the drug semaglutide.
Dr Louis Aronne, director of the Comprehensive Weight Control Center at Weill Cornell Medicine, in New York, said the findings showed obesity should increasingly be treated like other chronic diseases, with daly pills considered as 'treatment for life' in the same those taken for high blood pressure, high cholesterol and diabetes.
Obesity treatment also has the potential to replace many other medicines because excess weight drove such a wide range of disease, he added.
'The beauty of treating obesity is you are treating all of these things; you treat the glucose, treat the lipids, treat the blood pressure, all by treating the obesity,' he told the conference.
'If we could treat obesity effectively, we wouldn't need to treat all of the other cardio-metabolic risk factors and it could be highly cost effective.'
Dr Aronne said researchers are increasingly looking at whether obesity should be treated much earlier, before patients developed severe disease.
Professor Rachel Batterham, senior vice president of medical innovation at drug maker Lilly, also said obesity should be treated far earlier, before complications developed.
'It makes sense to treat earlier to prevent complications rather than waiting for the complications,' she said.
'Obesity is a disease that causes over 200 other complications,' she added, with research linking excess weight to diabetes, heart disease and at least 13 types of cancer.
Ken Custer, president of cardiometabolic health at the company, said: 'We've been waiting for a scalable solution and that's what we have here.'
He said the pills could be made using standard pharmaceutical manufacturing methods, similar to statins or blood pressure tablets.
Oral drugs are also significantly cheaper to distribute because they do not require refrigeration or injection pens, he added.