The study led by Dr Alan Kristal from Fred Hutchinson Cancer Research Centre showed that regular yoga practice may help prevent middle-age spread in normal-weight people and may promote weight loss in those who are overweight.
The researchers suspected that the weight-loss effect is related to do a sensitivity to hunger and satiety than the physical activity of yoga practice itself.
"In our earlier study, we found that middle-age people who practice yoga gained less weight over a 10-year period than those who did not," said Kristal.
"This was independent of physical activity and dietary patterns. We hypothesized that mindfulness - a skill learned either directly or indirectly through yoga - could affect eating behaviour," he added.
The study showed that people who ate mindfully - those were aware of why they ate and stopped eating when full - weighed less than those who ate mindlessly, who ate when not hungry or in response to anxiety or depression.
The team found a strong association between yoga practice and mindful eating but found no association between other types of physical activity, such as walking or running, and mindful eating.
During the study, Kristal and colleagues developed a Mindful Eating Questionnaire, a 28-item survey that measured a variety of factors like disinhibition - eating even when full; awareness - being aware of how food looks, tastes and smells; external cues - eating in response to environmental cues, such as advertising; emotional response - eating in response to sadness or stress; and distraction - focusing on other things while eating.
Higher scores on the mindfulness questionnaire overall (and on each of the categories within the questionnaire) was associated with a lower BMI, which suggests that mindful eating may play an important role in long-term weight maintenance, Kristal said.
"Mindful eating is a skill that augments the usual approaches to weight loss, such as dieting, counting calories and limiting portion sizes. Adding yoga practice to a standard weight-loss program may make it more effective," he added.
The study is published in the Journal of the American Dietetic Association.