People who are obese are up to 80 times more likely to develop diabetes, a leading health charity said on Friday.

In Britain, which has the fastest growing rate of obesity in the developed world, one in five adults has a serious weight problem.

Obesity is not the only risk factor for diabetes, but Diabetes UK said in a report that people who have a body mass index (BMI) of more than 30 are 10 times more likely to develop the illness

If their BMI is above 35 for 10 years, the risk increases to 80 times compared to a person of average weight.

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

“Diabetes can lead to serious complications such as heart disease, stroke and blindness,” he added in a statement. “In short, obesity can take years off people’s lives.”

Scientists use the BMI, calculated by dividing weight in kilograms by height in metres squared, to measure weight and obesity. A BMI of 30 or more is considered obese.

In the last 22 years, obesity in Britain has nearly trebled in adult women and almost quadrupled in men. The rise is fuelling an increase in diabetes, which experts predict will affect 3 million people in Britain by 2010.

Diabetes is a chronic illness caused by a deficiency or lack of insulin. The hormone produced by the pancreas helps glucose, or sugar, from food get into cells.

About 90 percent type 2, or adult-onset diabetes cases, is linked to being overweight or obese. Smallwood said the onset of diabetes could be delayed or prevented if overweight and obese people make lifestyle changes and lose weight.

“It’s a problem that must be tackled now,” he added.