The ancient practice of yoga may do more ! than just improve strength and flexibility-it could also help people shed extra pounds in middle age, according to the first study to examine yoga's impact on weight loss.
Investigators report that overweight 45- to 55- year-olds who regularly practiced yoga lost an average of five pounds during the course of a decade. At the same time, normal-weight yoga practitioners gained three fewer pounds than people who did not practice yoga during this same 10-year period.
To examine the relationship between weight loss and yoga, researchers at the Fred Hutchinson Cancer Research Center in Seattle surveyed 15,500 healthy men and women ages 53 to 57. The participants were queried on their weight history and physical activity since they were 45 years old.
Only 132 of the people surveyed said they practiced yoga regularly for at least four years. However, overweight yoga practitioners lost approximately five pounds, on average, during a 1O-year period, while those who did not practice yoga gained an average of 13.5 pounds. people who were at a normal weight and regularly practiced yoga gained three fewer pounds during this period than those who didn't practice yoga (9.5 pounds compared with 12.6 pounds).
"I was very surprised with the results. Considering that people gain approximately a pound a year during this time [of their lives], this is pretty substantial," says lead researcher Alan R. Kristal, associate head of the Cancer prevention Research Program at the Hutchinson Center and a professor of epidemiology at the University of Washington. "Even the best dietary and behavioral approaches to weight loss are not all that effective. Now, with yoga, we have one more tool that may help with weight loss," he says.
Kristal says he isn't certain how yoga helps promote weight loss and maintenance, particularly because only vigorous yoga would burn enough energy to meet the American College of Sports Medicine's guidelines for weight management. However, he speculates that yoga could be indirectly beneficial by encouraging healthier eating and exercise habits. For example, yoga teaches body awareness and encourages physical discipline, so it may help a person know when they're full and promote a general sense of well-being, he says.
Dr. Janine Blackman, medical director of the University of Maryland's Center for Integrative Medicine, has another theory-the "mindful,, nature of yoga creates a healthier response to stress, lowering stress hormones and preventing stress-driven eating.
"Middle age is a full time in life," Blackman says. 'A better response to this stress can lower cortisol and other stress hormones, which helps physiologically. If cortisol is elevated, you're more likely to have insulin resistance, which is central to obesity."
Both Blackman and Kristal agree that more research is needed because of this study's limitations. People in this study did not report the type of yoga they practiced-that's important, since the physical intensity of specific yoga techniques varies. The survey was also self-reported, relying on people's memories and assuming that they were honest. Kristal hopes a future observational study will help fill in these gaps and that, eventually, a large, randomized trial will be conducted.
In the meantime, Blackman, who recommends gentle yoga to her patients, says she will continue to do so. "Gentle yoga is a great way to ease into an active life, especially since overweight people are already less likely to exercise because it hurts," she says.