Oprah just bought into Weight Watchers. But does it work?

After 12 months of dieting, people who followed Weight Watchers lost 2.6% more weight than those who followed the comparison group, the analysis found. But people on NutriSystem lost 3.8% more than the comparison group, while those who followed Jenny Craig lost 4.9% more. All of the health plans studied "had modest improvement, and most of the weight-loss was short-term," said David Ludwig, director of the New Balance Foundation Obesity Prevention Center at Boston Children's Hospital. Weight Watchers has "been one of the chief advocates of calorie counting," said Ludwig, author of an upcoming book called Always Hungry?: Conquer Cravings, Retrain Your Fat Cells, and Lose Weight Permanently. "That concept may work in the lab, but it's becoming increasingly ineffective in the real world. ... You can cut back on calories, but that disregards a basic fact that our body fights back as we lose weight. Our hunger increases, but our metabolism slows down." USA TODAY Late Weight Watchers founder: Food isn't 'remedy' for problems Dietitian Sue Cummings credits Weight Watchers with updating its message over the years, based on important scientific findings, while refusing to embrace every new fad. "It never really fell into any of that quackery – the quick weight-loss fixes, where if it sounds too good to be true, it probably is," said Cummings, coordinator of clinical programs and services for the Massachusetts General Hospital Weight Center in Boston. Cummings said Weight Watchers is the only commercial program to which she would refer patients. The fact that people often fail to lose weight or maintain that loss, even with the help and support provided by Weight Watchers meetings, shows that the USA has an uphill battle in fighting the obesity epidemic, Cummings said. Two in three Americans are overweight, while one in three is obese. USA TODAY Oprah buys 10% of Weight Watchers, stock soars "Weight watchers is good initial, relatively low-cost, non-invasive program," said Philip Kern, a professor of medicine in the division of endocrinology at the University of Kentucky, noting that it's hard to compare one program with another, because "people are going to do what they want," regardless of their diet program's instructions. "Some people need more motivation or professional help than (Weight Watchers) can give," Kern said. "And of course it is very hard to modify behavior when the bad behaviors are all around us''