Scientists uncover new weight loss hormone

Scientists have discovered an appetite-suppressing hormone which could help to tackle Britain's epidemic of obesity.

The PYY3-36 hormone is released from the stomach after eating and tells the body it is full. The amount released depends on the calorific content of the meal.

Researchers from Imperial College London found the hormone can reduce the amount of food a person wants to eat each day by a third.

They hailed the discovery as a major breakthrough in the study of obesity and research into new ways of treating the soaring numbers of people who suffer from weight problems.

Professor Stephen Bloom, who led the study, said: "The study that PYY3-36 suppresses appetite could be of huge benefit to those struggling with weight problems.

"With over one billion people across the world now extremely overweight, it is vital that this problem is tackled."

He added: "It may (be possible) to identify foods which cause the release of more PYY3-36, helping to naturally limit appetite, or it may be possible to create a tablet with a similar effect, providing an excellent natural and safe long-term treatment for obesity."

Current "last resort" treatments for obesity involve risky surgery such as stomach stapling, which permanently changes the way that people can eat food, or dieting pills which can have side effects.

Scientists say the discovery of a natural appetite suppressant could help millions of people who do not want to take conventional drugs or resort to surgery.

Researchers gave six people an infusion of the hormone and compared their reactions with six other volunteers who were given a "dummy" saline infusion. For the next 24 hours, the calorific intake of the volunteers who received the hormone infusion dropped by a third.

They also reported a 40 per cent drop in perceived levels of hunger within 12 hours of the infusion. The team's Dr Rachel Batterham said: "Rather than using extreme measures such as dieting pills or even surgery, PYY3-36 should be able to provide a far safer and effective alternative."

For the first time, there are now more overweight people in the world than there are underweight. Some experts have blamed the obesity epidemic on the increasing popularity of takeaway and junk food.

One in five British adults is now clinically obese and more than half are sufficiently overweight that it causes them health problems. One million children are classed as obese, and the condition causes 30,000 premature deaths a year from illnesses caused or worsened by it.

Treating obesity costs the NHS £500 million a year and the economy £ 2billion annually, mainly through the 18 million working days lost through illhealth.

In the United States, one man is suing a number of fast food chains, claiming that he has become obese because the outlets do not offer healthy alternatives and do not give warnings about the high-fat content of their products.

A spokesman for the charity Toast (The Obesity Awareness and Solutions Trust) said: "This is an interesting breakthrough and could help some people, but I think these scientists have fallen into the trap of thinking that obese people eat because they are hungry.

"The alcoholic doesn't drink because he is thirsty. A lot of obese people are not hungry when they eat - they are eating because they are using food to cope with life, and that needs to be addressed by doctors."

Doctors class people as overweight or obese by calculating their Body Mass Index (BMI), which is their weight in kilograms divided by their height in metres squared. A BMI of under 25 is considered healthy, between 25 and 30 is classed as overweight and more than 30 is regarded as clinically obese.

Breastfeeding can also protect children against obesity, research suggests. But fewer women in the UK now breastfeed their babies, meaning that youngsters are being put at a disadvantage in the first few months of life.

Being clinically obese is linked to a twentyfold increased risk of diabetes. Experts say that the number of people with the condition is set to double because of rising levels of weight problems.

Research also suggests that women with a waist of more than 80cm (31.5in) will have slight health problems as a result of their weight, while those whose waists are more than 88cm (34.5in) face substantially higher risks. For men, the measurements are 94cm (37in) and 102cm (40in) respectively.