Scientists have pinpointed a reason why people with Indian ancestry may be more prone to weight problems.

They have found this group is more likely to carry a gene sequence linked to an expanding waist line, weight gain and type 2 diabetes.

The sequence, discovered by a team led by Imperial College London, is carried by 50% of the population - but is a third more common in Indian Asians.

It is hoped the Nature Genetics study could lead to new obesity treatments.

The finding might provide a possible genetic explanation for the particularly high levels of obesity in Indian Asians, who make up 25% of the world's population, but who are expected to account for 40% of global cardiovascular disease by 2020.

The gene sequence sits close to - and possibly influences - a gene called MC4R, which regulates energy levels in the body by influencing how much we eat and how much energy we expend or conserve, and which has been directly implicated in rare forms of extreme childhood obesity.

The researchers discovered that the sequence is associated with a 2cm expansion in waist circumference, a 2kg gain in weight, and a tendency to become resistant to insulin, which can lead to type 2 diabetes.

Preventative measures

Lead researcher Professor Jaspal Kooner said the genetics behind obesity and its related health problems had been little understood.

He said: "A better understanding of the genes behind problems such as diabetes and cardiovascular disease means that we will be in a good position to identify people whose genetic inheritance makes them most susceptible.

"We can't change their genetic inheritance. But we can focus on preventative measures, including life-style factors such as diet and exercise, and identifying new drug targets to help reduce the burden of disease."

Professor Peter Weissberg, medical director of the British Heart Foundation, which funded the study, said it had long been established that Indian Asians were more susceptible to heart disease than white Europeans.

He said: "This study is important because it provides a potential genetic 'flag' by which doctors may be able to identify people who would gain great health benefits from help to avoid gaining weight.

"Secondly, the findings give us new insights into the biology that makes some people more susceptible to heart disease than others.

"It is one of several recent genetic studies that promise to shed new light on the causes of heart disease and how to avoid it."