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 13 1/2 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.
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.
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.
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.
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."