## Binge-eating linked to heredity

> #### Altered gene found in some overeaters

> Two new studies provide additional evidence that genetics, rather than willpower, play a key role in eating disorders.

> BOSTON, March 19 - Binge-eaters who say they can't help it may be right. A study suggests a weak gene, not feeble willpower, may be the cause for some people. The research may point the way to a future pill to tame their appetites.

> THE JOINT Swiss-German-American study makes the strongest case yet that genetic mistakes can cause an eating disorder, researchers say. Traditionally, eating behavior has been viewed as complex and cultural in its causes.

> "Willpower is not always important to reduce weight. Some people can by willpower. Some cannot, and I think these patients have a hard time," said Dr. Fritz Horber, the leader of the binge-eating study at the Hirslanden Clinic in Zurich, Switzerland.

> Researchers have been trying to understand the reasons for an epidemic of obesity, which raises the risk for heart disease, diabetes and many other ailments. About 30 percent of American adults are obese, up from 14 percent 25 years ago, according to government data. The surge is widely blamed on abundant high-calorie foods and sedentary lifestyles.

> CAUSES OF OBESITY
> However, some researchers have also begun to link several genes to obesity, implicating heredity as an important underlying factor. Increasingly, eating problems are thought to stem from a subtle interaction of lifestyle and multiple genes.

> Overwieght in America FAQ
> Sources: AHA, NIH, CDC, NHNES

> - "Thirty-four percent of U.S. adults are considered overweight, and an additional 31 percent are obese.
> - "Anyone with a body mass index (a ratio between your height and weight) of 25 or above -- that's someone, for example, who is 5-foot-4 and 145 pounds -- is considered overweight, according to the National Institutes of Health. Anyone with a body mass index of 30 or above -- such as someone who is 5-foot-6 and 186 pounds -- is considered obese."
> - "Three hundred thousand people die each year due to obesity-related causes, making it the second-leading cause of death after smoking. Being overweight or obese increases the risk of hypertension, heart disease, stroke, diabetes and some cancers."
> - "Fifteen percent of youngsters ages 6 to 19 and 10 percent of children 2 through 5 are considered seriously overweight. "
> - "About 45 percent of women and 25 percent of men are trying to lose weight at any one time, but only one-fifth are using the recommended combination of fewer calories and increased exercise."
> - "Americans spend more than $33 billion a year on weight-loss products and services. However, the economic cost of obesity in the United States was about $117 billion in 2000."
> - "Choose low-fat, lean foods from the five major food groups; eat sensible portions, and use fats, oils, sweets and salt sparingly. Total fat intake should be no more than 30 percent of daily calories. Exercise moderately for at least 30 minutes on most days. If you need to lose weight, do so gradually -- aim to lose about 10 percent of your body weight over 6 months."
> - ("How many Americans are overweight or obese?","What's the rate of obesity among adults in my state?","How do doctors define overweight versus obesity?","How many deaths are attributed to obesity each year?","Are children affected by the epidemic?","Why are so many dieters doomed to fail?","How much do we spend on obesity?","What should we be doing?")
> Probably the most common eating disorder, binge-eating strikes up to 4 million Americans, according to the National Institutes of Health. Binge-eaters, who are usually but not always overweight, frequently and compulsively stuff themselves - often in secret - and feel ashamed afterward.

> In this study, which was published Thursday in The New England Journal of Medicine, the researchers focused on a gene linked to obesity in earlier studies. Known as the melanocortin 4 receptor gene, it makes a protein by that name that helps stimulate appetite in the brain's hunger-regulating hypothalamus. If a mutated gene makes too little protein, the body feels too much hunger.

> BINGE-EATING GENE
> The researchers considered 469 severely obese white adults - a quarter of them binge-eaters. However, the disorder was much more common among the 5 percent with the mutated gene. All of them were binge-eaters, compared to just 14 percent of those with no mutated gene.

> In another study in the same journal issue, a British team reported finding mutations of the same gene in more than 5 percent of 500 severely obese children. The genetic link was so strong that the researchers could use results from chemical tests on their genetic DNA to predict how much the children would eat at a meal.

> Horber, the Swiss researcher, said other eating disorders, including other types of bingeing, probably stem from a variety of genes and environmental factors. However, he said the still-unnamed binge-eating syndrome tied to this gene is especially important because it is perhaps the most stubbornly resistant to dieting and exercise.

> A RELIEF FOR EATERS
> Horber said the binge-eaters in his study felt a wave of relief from guilt when they learned of the genetic cause behind their compulsion. Dr. Stephen O'Rahilly, one of the British study's researchers at the University of Cambridge, said one family in that study was so ecstatic over evidence of a physical cause that they made themselves T-shirts saying, "We've got an MC4 mutation."

> Eric Ravussin, a Louisiana State University researcher on obesity genetics, said, however, that without more biochemical proof, he remains "a little bit skeptical" that these mutations - and not others located nearby on the same chromosome - are the syndrome's precise cause.

> But Dr. Joel Habener, a diabetes expert at Boston's Massachusetts General Hospital who co-wrote an accompanying editorial, said the Swiss-led study demonstrates either the "genetic cause or a very strong association."

> And he agreed with the researchers, who said future drugs acting like the melanocortin 4 receptor protein may compensate for the genetic defect. Habener said such chemicals are apt to be small molecules that can be delivered as pills.

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