Wider access to weight-loss injections on the NHS could deliver significant economic gains by cutting sick days and easing the burden of obesity-related illness, new research suggests.
A study of 421 NHS patients using the latest generation of obesity drugs found the number of sick days taken fell by a third within three months of starting treatment. Combined sick leave dropped from 517 days in the three months before starting the jabs to 334 days after three months of use, according to data from Oviva, the UK’s largest provider of weight-loss support services.
After six months, 77 per cent of patients reported taking no sick leave at all — up from 63 per cent before starting treatment.
The findings highlight the potential economic impact of rolling out obesity injections more widely. Government figures show UK workers took 149 million sick days in 2024, down from a pandemic-era peak but still nearly 10 million more than pre-2020 levels.
Health Secretary Wes Streeting has previously described obesity as a key drag on the workforce, with people living with obesity taking “an extra four sick days a year on average” and many leaving employment altogether.
“These drugs could have colossal clout in our fight to tackle obesity and get unemployed Britons back to work,” Mr Streeting has argued, backing the medicines as a tool for reducing economic inactivity.
Government modelling suggests that a widespread rollout could save the taxpayer £5bn annually through productivity gains and lower healthcare costs. Obesity is estimated to cost the UK economy around £98bn a year, including £15bn in lost productivity and £19bn in direct NHS spending.
Despite political enthusiasm, the rollout of jabs such as Mounjaro, made by Eli Lilly, has been slow. At the end of June, 32,000 patients were still waiting for an NHS weight management appointment, while only 1 per cent of eligible patients currently receive treatment, according to Oviva.
A quarter of a million people across England are expected to be prescribed Mounjaro on the NHS over the next three years, but demand is already outstripping supply.
Martin Fidock, UK chief of Oviva, urged ministers to accelerate distribution: “The Chancellor talks about firing up Britain’s productivity but doesn’t address the millions who are locked out of work by poor health. People living with obesity are twice as likely to be off sick, yet Britain’s postcode lottery for healthcare means just a fraction of patients get access to treatment.”
The average patient in Oviva’s study was 49 years old — an age group where obesity typically peaks and comorbidities such as anxiety, depression and hypertension are common. Alongside the reduction in sick days, many patients reported lifestyle changes, including drinking more water and eating vegetables more regularly.
Research has also linked the new generation of weight-loss treatments to broader health benefits, including halving the risk of death from cardiovascular disease and reducing cancer risks.
Earlier this year, the Tony Blair Institute suggested weight-loss jabs could be offered to half of all UK adults as part of a national obesity strategy. However, if all 26 million Britons with a BMI of 27 or above were prescribed the drugs, the annual bill would be about £38bn — around 17% of total NHS spending.
The debate now facing policymakers is whether the productivity gains and reduced healthcare costs outweigh the upfront price of scaling up access.
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Weight-loss jabs could slash UK sick days and boost productivity, study finds