By Marjory Inglis, health reporter

SCIENTISTS HAVE discovered the genetic answer to why some people get fat and others don’t, with the help of nearly 7000 Tayside volunteers.

But it’s no signal for fatties to give up the battle of the bulge and head for the biscuit barrel, abandoning all restraint on calorie intake.

Obese people can now claim that nature decreed they would be large, after scientists announced yesterday they had found the genetic variation common to the super sized. They’re excited but they’re certainly not telling big people there’s nothing they can do about their weight.

Professor Andrew Morris, a diabetes specialist at Ninewells Hospital in Dundee and one of the authors of the report published yesterday, warned last night that a balanced diet and regular exercise remained the key to weight control.

He has recruited several thousand people in the Tayside and Fife area to participate in research that is trying to crack the genetic code of a number of common diseases. The hope is that by solving the genetic clues to diseases, better treatments can be developed that are targeted at those most likely to benefit.

Volunteers had their height, weight and blood pressure measured, as well as donating blood samples which carry the genetic code of each individual.

It was these samples, which scientists investigated along with the samples of tens of thousands of other volunteers across Europe, that showed people with a certain genetic variation really are more likely to get fat than those without the variation.

“Our volunteers have played a significant part in this major, international scientific breakthrough,” said Professor Morris. “This is the first time we have been able to make a clear genetic link to obesity.

“However diet and exercise remains the cornerstone approach to the treatment and management of obesity. We must emphasise this discovery is not giving people an out.”

Professor Morris, who holds the chair of diabetic medicine at Dundee University and is a key adviser to the Scottish Executive Health Department, worked with scientists in Exeter and Oxford on the study that uncovered the genetic link to obesity.

The study, funded by the medical research charity the Wellcome Trust, found people with two copies of a particular gene variant have a 70% higher risk of being obese than those with no copies. These people are on average 3kg heavier than a similar person with no copies.

“As a nation, we are eating more but doing less exercise, and so the average weight is increasing, but within the population some people seem to put on more weight than others,” said Professor Andrew Hattersley from the Peninsula Medical School, Exeter, one of the co-authors of the report published online in the journal Science.

“Our findings suggest a possible answer to someone who might say ‘I eat the same and do as much exercise as my friend next door, so why am I fatter?’ There is clearly a component to obesity that is genetic.”

Professor Morris paid tribute to the Tayside volunteers and the excellent co-operation the research team was given by GPs locally.

“Many places internationally struggle to do this type of research because they don’t have several key factors, including the magnificent support of the local population and unified healthcare system that we have here in Tayside,” said Mr Morris. “We are uniquely placed to excel.”