The research was led by Dr Jonathan Pearson-Stuttard, a public health scientist based at Imperial College London and head of health analytics at the LCP consultancy.
He said: “This is a first-of-its-kind study, showing the costs of obesity across the whole health system.
“As weight increases through the BMI categories – from healthy to overweight to obese – costs increase and use of healthcare resources increase.
“These costs are not just from living with obesity, but all the different conditions it results in – such as heart disease, stroke and back pain. People collect more and more obesity-related conditions over time.
“By far the biggest cost to the NHS is hospital admissions. We know obesity can cause a range of hospitalisations including heart attacks, stroke, heart failure. It also increases the risk of cancers.
“The ill-health and costs associated with obesity compound over time. Not only is that impacting individual health, but also costs to the NHS and the economic workforce.”
The study follows warnings from the Office for National Statistics that long-term sickness has hit a record 2.5 million, with one in 14 workers on such leave.
Back and musculoskeletal problems linked to home-working, excess weight and insufficient exercise since the pandemic are among factors fuelling the trend.
Dr Pearson-Stuttard said tackling obesity was essential to boosting the UK’s economic prosperity.
He said: “Two of the biggest challenges for the UK economy is reducing demand on the health system, and increasing economic productivity.
“Tackling obesity could really move the needle on both of these. People with obesity have quite predictable complications, but if you can control their weight and the risk of conditions, you will dramatically reduce demand for healthcare services.
“Obesity is a big reason behind the rise in long-term sickness and inactivity in the UK workforce. In the last 20 to 30 years we have seen a big increase in people with multiple chronic conditions, which means they are not working.”
Earlier this year, restaurateur Henry Dimbleby resigned as the Government’s food tsar and accused the Tories of “insane” inaction against obesity.