A team of researchers at the Imperial College of London [Images] claim to have identified a natural hormone that may offer the obese a way of reducing their appetites.

The hormone, called oxyntomodulin, is produced by the small intestine after a meal.

In a trial, a group of 14 obese and overweight subjects self-administered doses of the hormone 30 minutes before breakfast, lunch and dinner; after four weeks, they had lost an average 2.3 kilos.

'By giving the overweight subject oxyntomodulin we are fooling the brain, in a very natural way, into thinking it has just eaten a meal and is no longer hungry,' the New Scientist quoted Steve Bloom, who led the trials, as saying.

The researchers found the hormone reduces an individual's daily intake by an average of 170 kilocalories after the first injection and upto 250 kcal per day at the end of four weeks.

It also reduced the levels of adipose hormones and leptin -- a hormone responsible for regulating the body's energy expenditure �- of the participants. The researchers also found a reduction in the levels of adipose hormones. Adipose hormones encourage the build up of adipose tissues where fat cells are stored.

The researchers said there were no significant side effects to the hormone injection during the trial and patients did not develop tolerance to the effects of the hormone.

"The big thing is that you have had an oxyntomodulin administration from your own gut switching off your hunger after a meal every day of life. This is the way you normally lose your appetite after a meal," Bloom said.