'Skinny gene' could lead to weight-loss pill

The gene governs whether the body piles on pounds or burns them off, researchers found.

Further study could lead to drugs that trick the body into shedding fat.

Ultimately, such pills could give men and women a trim body without any visits to the gym.

The finding follows the discovery of an obesity gene and could help explain why some seem to eat what they like without putting on weight, while others constantly fight the flab.

Researcher Dr Jonathan Graff, of the University of Texas, said: "From worms to mammals, this gene controls fat formation.

"It could explain why so many people struggle to lose weight and suggests an entirely new direction for developing medical treatments that address the current epidemic of obesity.

"People who want to fit in their jeans might some day be able to overcome their genes."

Dr Graff focused on a gene that was named adipose when it was discovered in rotund fruit flies almost 50 years ago.

He turned the gene on and off at different stages in the lives of a range of animals and in various parts of their bodies.

Mice with highly active genes ate as much, or more, than normal mice, yet remained leaner.

They also appeared to be at lower risk of diabetes.

But rodents with lower adipose activity were fatter, less healthy and developed diabetes.

Tests on flies suggested that the gene acts as a dimmer switch, with different combinations leading to different levels of fat accumulation.

We all carry two copies of every gene. Flies with two inactive genes were fat and struggled to get about.

Those with just one inactive gene were slightly plump, while those with two fat-burning genes were a normal weight.

The results suggest that the gene is a master-switch which tells the body whether to burn fat or pile it on.

A similar gene is known to exist in humans and if it has the same effect on the human body, could pave the way for anti-obesity drugs.

Treatments could include drugs that produce the same effect on the body as the gene or pills that boost its activity.

Dr Graff, whose findings are published in the journal Cell Metabolism, said: "This is good news for potential obesity treatments. It is like a volume control instead of a light switch.

"It can be turned up or down, not just on or off. Maybe if you could affect this gene, even just a little bit, you might have a beneficial effect on fat."