October 23, 2008
New Developments Could Allow People To Eat And Lose Weight
Scientists are working to develop foods that slow down the digestive system and make the body feel full.
The foods being developed by Peter Wilde and colleagues at the Institute of Food Research in Norwich, England will help trigger a signal to the brain that suppresses appetite.
"That fools you into thinking you've eaten far too much when you really haven't," said Wilde. From his studies on fat digestion, he said it should be possible to make foods, from bread to yogurts, that make it easier to diet.
Doctors see great potential in the use of these foods in the fight against obesity.
"Being able to switch off appetite would be a big help for people having trouble losing weight," said Steve Bloom, a professor of investigative medicine at London's Imperial College, who is not connected to Wilde's research.
Other methods of controlling appetite are also underway, including chemical injections or implantable devices that interfere with the digestive system.
Bloom said that regulating appetite through modified foods is theoretically possible. Other mechanisms in the body, like cholesterol production, are already routinely tweaked with medicines.
But Bloom warned that controlling appetite may be more challenging. "The body has lots of things to prevent its regulatory mechanisms from being tricked," he said.
Fat normally gets broken down in the first part of the small intestines. When you eat a high-fat meal, however, the body can only digest the fat entirely further down in the intestines. That sparks a release of hormones that suppress appetite.
Wilde's approach copies what happens with a high-fat meal: he coats fat droplets in foods with modified proteins from plants, so it takes longer for the enzymes that break down fat to reach it.
That means that the fat isn't digested until it hits the far reaches of the intestines. At that point, intestinal cells send a signal telling the brain it's full. This effectively suppresses the appetite.
A different method from scientists at the University of Newcastle uses a seaweed extract to reduce fat absorption by cutting the level of glucose digested by the body before it gets broken down in the large intestine.
Drugs such as orlistat, marketed as Xenical by Roche Holding AG, and Alli by GlaxoSmithKline PLC work in a similar way by blocking fat absorption. However, orlistat has known side effects including gas and diarrhea.
"It would be very helpful to reduce people's calorific levels by stealth, so they don't notice there's been a change," said molecular physiology professor Jeffrey Pearson, who is leading the Newcastle research. "People don't want to completely change their lifestyle and stop eating. ... This lets them indulge again."
Food companies and pharmaceutical firms are also exploring ways to tinker with appetite. In 2004, Unilever bought the rights to a South African plant traditionally chewed by tribesman to ward off hunger.
A small study found that people given the plant extract, hoodia gordonii, for 15 days had slashed their food intake by 1,000 calories compared to people on a placebo. A Unilever spokesman said the extract would be added to a food or beverage and could hit the market within a few years.
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