Scientists in Australia have found that people with family history of diabetes put on extra weight from overeating compared to people with no family history of the disease.

The research involved researchers from the Garvan Institute of Medical Research overfeeding a group of healthy people - half with genetic markers for type 2 diabetes and half with none - for one month.

The results showed after eating additional 1250 calories per day - comparable to about 5 plain croissants - those with pre-existing family history put on 3.4kg while those with none put on only 2.2kg.

The study was planned based on the overeating habits of people during festive seasons.

Lesley Campbell, co-author of the study who is a researcher at St Vincents Hospital said while type 2 diabetes was a highly heritable condition, not all who had a background history of would develop it.

He said it was generally understood that people with type 2 diabetes had developed it due to being obese or overweight.

Prof Campbell, however, believed additional weight gain that occurred in 80 to 90 per cent of type 2 diabetics is part of the disease, and not the primary cause.

Prof Campbell said, Something that drives people to get diabetes, drives them to put on weight.

My theory is they can't help it with their genetics - they're predisposed to get that way.

The results also showed the people with family history of diabetes who had gained weight, also developed insulin resistance, after 3 days of overeating.

Insulin resistance is a condition when cells in the body become less sensitive to the insulin hormone.

At the end of the study, both groups developed insulin resistance and their livers were observed to carry accumulated fat.

The study revealed that people with a family history of diabetes consumed more food than those without family history, said Prof Campbell.

Australia Medicine