Researchers found that overweight people in their 50s who regularly practiced yoga lost about five pounds over 10 years, while a group in the same age range gained about 13½ pounds over the same period.
Middle-aged people of normal weight generally put on pounds over 10 years, but those who did yoga gained less weight than those who didn't practice yoga.
The link between yoga and weight loss has nothing to do with burning calories, said Alan Kristal, one of the researchers from the Fred Hutchinson Cancer Research Center who co-authored the study.
"Except for very strenuous yoga practices, you don't really burn enough energy to make any difference in terms of weight," said Kristal, who has practiced yoga for 10 years.
Instead, he thinks yoga helps keep people more in tune with their bodies and eating habits and aware of bad habits, such as eating because of stress, boredom or depression.
"You become very sensitive to the feeling of being stuffed," he added.
The researchers collected data from 15,500 people between the ages of 53 and 57 who were asked about exercise, weight, health and diet histories. The findings, published in the July/August issue of Alternative Therapies in Health and Medicine, showed that those who practiced yoga tended to avoid junk food and overeating because they wanted to respect their bodies.
Mary Imani, a yoga teacher at 8 Limbs Yoga Center, said it's difficult to eat heavily and do yoga. "It's hard to do certain movements when you've just had a slice of pizza," she said.
Gloria Supplee, a 59-year-old who has practiced yoga for five years, said yoga has seemed to help her maintain her weight. "Having your body in a balanced position, your body is more likely to desire nutrients," she said.
Gary Miller, who studies obesity and weight loss at Wake Forest University in North Carolina, called the research encouraging, but said it's difficult to prove a direct influence from a single study.
Most yoga fans say weight loss is just an added bonus from the disciplined form of meditation, controlled breathing and prescribed postures.
"Yoga does many things," said Kathleen Hayes, who has practiced yoga for four years and manages a yoga studio in Seattle. "It builds strength, flexibility and clarity."
At 54, she says it has helped her maintain her weight.
For the 47-year-old Imani, a yoga practitioner for nearly two decades whose weight has fluctuated since she became menopausal, "It's all about trying to find harmony and balance."