Obesity is the biggest risk factor for type 2 diabetes, however young people who are obese can reduce their risk of developing diabetes later on if they lose weight early enough, a new study has found.

UK researchers looked at the body mass index (BMI) of almost 5,000 men when they were aged 21 and again when they were aged 50.

They found that men who had a high BMI at the age of 21, but had managed to lower their BMI by the time they reached the age of 50, had similar or even lower rates of diabetes as people who had been a normal weight when younger.

In other words, the effects of having a high BMI early in life may be reversible when it comes to diabetes.

"Even in men who were relatively thin in early life compared to more recent men, higher levels of fatness in early adult life appear to be associated with later diabetes. However, effects of early body mass appear to be reversible by subsequent weight loss," the researchers from St George's University of London said.

They added that these findings ‘have important implications for type 2 diabetes prevention, especially in more recent adults with high levels of obesity'.

Details of these findings are published in the journal, BMJ Open.