Lean gene puts fat in the metabolic fire

THE notion of no pain, no gain may be a thing of the past. Scientists believe they have isolated the gene which controls the burning of fat in the body, raising the possibility of an effortless treatment for obesity.

The discovery of the lean gene by a team of French and US scientists goes a long way to explaining why some people can consume large amounts of food and not be a gram overweight, and others whose lifestyle embraces every form of diet and exercise fad cannot lose weight.

The potential dream gene for the overweight is UCP2, as it has been found to trigger the creation of a protein that activates the burning of fat. Everybody has the protein, but in stronger concentrations in the body it prompts the burning off more dietary fat rather than its conversion into dreaded body fat.

UCP2 may also help treat some forms of diabetes, according to the team which published its findings in this month's issue of Nature Genetics.

A perpetual question of life has been why one person can indulge in everything and not put on weight, while another on the same diet is overweight. The explanation, according to Prof Daniel Ricquier of the French Centre for Research of Molecular Endocrinology, is a process of cellular combustion with UCP2 at the heart of the process.

"It helps to dissolve energy by turning it into heat," he explained. "When we eat, part of the food is digested and the rest goes to our cells. Some of it is stored in our cells in chemical form, but some is consumed, or burned. UCP2 creates the protein that sets off the combustion process."

Treatment for obesity has concentrated on reducing appetite or increasing metabolism. UCP2 raises the possibility of not putting on weight-regardless of diet, and now has researchers scampering for drugs likely to boost UCP2 levels. University of California researchers have already discovered drugs that can increase UCP2 in obese people.

The real medical benefits should be with "people who are unavoidably obese", predicted Dr David McConnell, Professor of Genetics at Trinity College Dublin. But he dampened expectations that UCP2 would overcome problems of overeating, lack of exercise and poor-diet, the common causes of obesity. "It would be a pity if they discovered a drug that made up for overeating or lack of exercise. But maybe everybody might not agree with me."

This breakthrough, nevertheless, was potentially the equivalent of the discovery of insulin used to treat diabetes, he said. "Scientists have been very interested in trying to find why some people become obese and most don't. They have been trying to find the molecular basis of this. UCP2 is part of the story emerging over the past five years."