Obesity is a major killer in the UK

Mice fed a high-fat diet lost 30% of their body weight in just four weeks on the treatment - originally designed to combat cancer.

However, scientists at the University of Texas warn development is at an early stage, and there is a high potential risk of side effects.

Their work is published in the journal Nature Medicine.

If even a fraction of what we found in mice relates to human biology, then we are cautiously optimistic that there may be a new way to think about reversing obesity. Dr Renata Pasqualini

Each fat cell in the body is connected to many tiny capillaries, giving them a rich supply of blood on which to thrive.

The researchers, at the University of Texas' Anderson Cancer Centre, identified a protein - prohibitin - that identifies fat cells and helps to construct the network of blood vessels that feed them.

They made the protein lethal by attaching it to another protein that triggers the cells in the blood vessels to commit suicide.

The modified combination proved to be highly effective at destroying fat tissue by dismantling its blood supply, effectively starving it to death.

When it was injected into mice they ate less food, and seemed to have a higher metabolic rate.

Side effects

The animals also seemed to tolerate the treatment well, showing few signs of side effects.

However, it is known that loss of fat cells can have detrimental effects - such as the accumulation of fat in non-fat tissue.

The researchers also warned that other research which has produced startling results in rodents has failed to produce the same effect in humans.

The next step will be to test the treatment on baboons, which do put on weight in the same way as humans.

Researcher Dr Renata Pasqualini said: "If even a fraction of what we found in mice relates to human biology, then we are cautiously optimistic that there may be a new way to think about reversing obesity."

The treatment is similar to a new class of anti-cancer drugs called angiogenesis inhibitors which starve tumours by cutting off their blood supply.

Dr Ian Campbell, chairman of the UK National Obesity Forum, told BBC News Online the drug appeared to work in a different way from those already on the market.

He said: "This is a fascinating study, and these guys are clearly at the leading edge of technology.

"But this is a long, long, long way from being a drug that is applicable to humans."

Professor Ian MacDonald, an expert on metabolic physiology, told BBC News Online he had concerns about what would happen to fat tissue destroyed by the treatment.

He said there was potential for it to lead to excessively high fat levels in the blood.

"This may end up being better as a preventative treatment to stop being becoming obese in the first place," he said.

Obesity is a significant, and growing problem throughout the developed world.