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

Oprah Winfrey – who has always been open about her struggles with weight – clearly believes in Weight Watchers. She just bought 10% of the company's stock, sending share prices soaring.
But does the 52-year-old Weight Watchers – the granddaddy of all commercial weight-loss plans – actually work?

Only modestly, research shows.
People who were randomly assigned to follow a Weight Watchers diet did only slightly better than a comparison group – people who tried to lose weight on their own or with the help of pamphlets or a few sessions with a health care provider – according to an April analysis of 45 earlier studies in Annals of Internal Medicine.

Jefferson Graham looks at how Weight Watchers is competing with calorie counting apps like MyFitnessPal and LoseIt to attract digital audiences, on #TalkingTech. By Jefferson Graham

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."

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.

"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."