Seriously, they needed a study for this

Obese dieters who reported eating less fat, exercising more and using prescription weight loss medications were more likely to lose weight than those who relied on diet foods and products, nonprescription diet pills and popular diets, according to a study.

"Despite popular perception that obese people are unable to lose weight, a substantial number of obese participants in our study did report successful weight loss, suggesting that some obese U.S. adults can and do lose weight," lead investigator Jacinda M. Nicklas, MD, MPH, MA, a clinical research fellow at Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, said in a news release.

Investigators analyzed data from the 2001-06 National Health and Nutritional Examination Survey, which collects demographic, health and health behavior information from non-institutionalized U.S. adults. From the sample of more than 4,000 obese adults with a self-reported body mass index of 30 or higher who participated in the in-home survey, they found that 63% of respondents tried to lose weight within the previous year.

Survey participants were more likely to report a weight loss of at least 5% of body weight if they reported eating less fat, exercising more and using prescription weight loss medications. Those who lost at least 10% were also more likely to have joined a weight loss program.

"Although national guidelines recommend a loss of 10% of body weight for improved health in the obese, studies have found that even a modest weight loss of 5% can lead to health benefits," Nicklas said.

Liquid diets, nonprescription diet pills and popular diets showed no association with successful weight loss, and those who reported losing more than 10% body weight were less likely to report eating diet foods and products, compared with those who lost less.

"Interestingly, although participants engaging in formal weight loss programs may be required to consume certain diet products or foods, in our study adults who said they used diet products were actually associated with being less likely to achieve at least 10% weight loss," Nicklas said. "This suggests that the structure of being in a program may be more important. It is possible that some dieters may be overeating diet products because they believe they are healthy, or low in calories."

In the study, prescription weight loss medications were associated with successful weight loss but were used by a small number of participants. "These results tell us that Americans use many weight loss strategies that are not associated with significant weight loss, including nonprescription weight loss medications," Nicklas said. "Public health efforts directing Americans to adopt more proven methods may be warranted."

The study is scheduled for publication in the May issue of the American Journal of Preventive Medicine. It is available in PDF form at http://bit.ly/I2c22m.