Almost one third of people in the Republic think they are overweight, a new survey has revealed.

Figures published ahead of World Diabetes Day revealed 34% of women think they are carrying extra weight compared to just a quarter of men.

People aged between 50-64 years are also more likely to believe they are heavier than average.

The data, released by pharmaceutical firm Novo Nordisk, highlighted the link between body weight and diabetes, a condition which will be recognised worldwide next Saturday.

Professor John Nolan, consultant endocrinologist at St James's Hospital, said four out of five people with diabetes are overweight.

"The number one risk factor for type 2 diabetes is obesity," said Prof Nolan.

"Greater weight means a higher risk of insulin resistance, because fat interferes with the body's ability to use insulin. If your insulin is not working correctly, you cannot regulate the sugar in your blood and this can develop into diabetes."

The medic said while overweight people over the age of 40 are at risk of developing diabetes, even a small amount of weight loss can make a big difference.

"If people lose just 5-7% of their body weight, they reduce their risk of developing diabetes and for those people who have diabetes, weight loss can dramatically slow the progress of the disease," Prof Nolan said.