Two international studies, published in Nature Genetics from tests across seven new gene variants discovered by scientists indicate that obesity is largely a mind problem.

The findings suggest point to the conclusion the brain plays the dominant role in controlling appetite, and that obesity cannot be blamed on metabolic flaws.

The studies examined samples from thousands of people for the tiniest genetic changes with the seven key variants appearing to be active in the brain.

This points to the brain's impact on appetite and eating behaviour being more important that any genetic variation which alters the body's ability to lay down or burn up fat.

All seven variants were picked up by a study led by Icelandic company deCODE Genetics, while in a similar stuidy six of the seven were also identified, independent study by an international team dubbed the Giant consortium.

In both cases the researchers scrutinised DNA samples from thousands of people to assess the impact of tiny changes, though each of the variants identified had a small impact on obesity, a person carrying all of them was on average only 1.5kg - 2kg heavier than normal.

It is estimated that as much as 70% of the variation in body mass index, a measure of obesity based on height and weight is down to genetics, rather than environmental factors.

Researcher Dr Kari Stefansson, of deCODE Genetics said in the report: "This suggests that as we work to develop better means of combating obesity, we need to focus on the regulation of appetite at least as much as on the metabolic factors of how the body uses and stores energy."

However the British Heart Foundation, expressed caution saying that this research adds to the growing body of evidence that some people are more at risk of becoming obese because of their genes.

They go on to say that it suggests that some people may be less able than others to resist the temptation to overeat because of their genetic background and it might start to explain why some people have no problem keeping their weight down whilst others struggle.

The study does not explain the current epidemic of obesity since these genes have been present for centuries and the obesity epidemic is a relatively new phenomenon."

Almost one in four people in the UK is now classified as obese, and expert predict the proportion will continue to rise sharply.