Blood Test Spots Yo-Yo Dieters

A simple blood test can spot people who are likely to get caught up in the yo-yo dieting cycle, shedding pound after pound only to regain them months later, researchers say.

A simple blood test can spot people who are likely to get caught up in the yo-yo dieting cycle, shedding pound after pound only to regain them months later, researchers say. The study, reported here at the American Heart Association Scientific Sessions 2003, shows that people with higher levels of the fat-fighting hormone leptin and the sugar-processing hormone insulin in their blood can’t seem to keep the pounds off. People who have high blood pressure also appear to be at risk, says lead researcher Kazuko Masuo, MD, PhD, of the Osaka University Graduate School of Medicine in Suita City, Osaka, Japan. Blood Test Identifies Yo-Yoers “The idea that a simple blood test can identify those that will yo-yo — before they even start their diet — is a new concept,” says Robert H. Eckel, MD, chairman of the AHA’s Nutrition, Physical Activity and Metabolism Council and professor of medicine at the University of Colorado Health Sciences Center in Denver. “Identification of these people will help us to help them long term.” About two-thirds of American adults are overweight or obese, increasing their risk of a wealth of health problems, from diabetes to heart disease, according to the most recent government statistics. But it’s not for lack of trying: Experts estimate that up to two-thirds of women and half of men are on a diet at any given time. “Part of the problem is that so many of these people are repeat dieters,” says Eckel, who moderated a discussion of the new findings. “They lose weight only to gain it back.” In fact, studies suggest that as many as two in three dieters are back on the merry-go-round within a year, he says. Dieting the Easy Part For the new study, researchers followed 52 obese young men with normal blood pressure and 61 obese men with high blood pressure who were on a low-calorie diet. As part of their weight-loss regimen, all the participants exercised for an hour a day. Six months later, about two-thirds of the men in both groups had successfully lost at least 10% of their body weight. But two years later, only about half of the successful dieters with high blood pressure had kept the weight off, compared with about two-thirds of those with normal blood pressure, Masuo says. Those who rebounded — regardless of blood pressure — tended to have higher levels of insulin in their blood at the beginning of the study, she says. Unsuccessful long-term dieters also had higher levels of leptin, a protein produced by fat cells in the body that has been shown to both reduce food intake and increase energy use, before they started the diet, Masuo says. If you’re one of the unlucky majority, don’t give up, the experts stress. Instead, work with a nutritionist or other health-care professional to find strategies that lower the chance of becoming an unsuccessful dieter, Eckel suggests. (Source: American Heart Association Scientific Sessions 2003, Orlando, Fla., Nov. 9-12, 2003. Robert H. Eckel, MD, professor of medicine, University of Colorado Health Sciences Center, Denver; chairman, AHA’s Nutrition, Physical Activity and Metabolism Council. Kazuko Masuo, MD, PhD, Osaka University Graduate School of Medicine, Suita City, Osaka, Japan. CDC: WebMD Health News: November 2003)