Obese people are up to 80 times more likely to develop diabetes than those of a healthy weight, a charity warned today.

Diabetes UK warned that the more overweight people become, the greater their risk of developing type 2 diabetes, which can lead to heart disease, stroke and blindness.

The charity's report, Obesity and Diabetes: A Heavy Burden, published today set out how the risk of developing diabetes rose progressively as an individual's body mass index (BMI) - a measurement of weight relative to height - increased.

It said someone with a BMI over 30 was up to 10 times more likely to get type 2 diabetes. Over a 10-year period, those with a BMI of more than 35 were up to 80 times more likely to develop diabetes than someone with a healthy BMI of less than 22.

Douglas Smallwood, chief executive of Diabetes UK, said: "These figures show the shocking extent to which obesity increases the risk of diabetes.

"Diabetes can lead to serious complications such as heart disease, stroke and blindness. In short, obesity can take years off people's lives. It's a problem that must be tackled now."

The report said medical studies had shown that lifestyles changes could delay or prevent the onset of type 2 diabetes. One US study found that small changes to diet, such as reducing fat intake, combined with 30 minutes of exercise a day, were effective in reducing diabetes risk.

About 100,000 people are diagnosed with type 2 diabetes in the UK each year. The number of people diagnosed with the condition has risen from around 200,000 in the 1950s to 1.8 million last year.

Doctors have blamed rising levels of type 2 diabetes on the growing number of overweight and obese adults. According to government figures, 22% of men and 23% of women in England are obese - a threefold increase since the 1980s.

Treating the ill health caused by poor diet costs the NHS at least £4bn a year. While 65% of men and 56% of women - 24 million adults - are either overweight or obese. About 16% of two to 15-year-olds are also obese.