SEATTLE - Regular yoga practice is associated with mindful eating, and people who eat mindfully are less likely to be obese, according to a study led by researchers at Fred Hutchinson Cancer Research Center.
The study was prompted by initial findings reported four years ago by Alan Kristal, Dr.P.H., and colleagues, who found that regular yoga practice may help prevent middle-age spread in normal-weight people and may promote weight loss in those who are overweight. At the time, the researchers suspected that the weight-loss effect had more to do with increased body awareness, specifically a sensitivity to hunger and satiety than the physical activity of yoga practice itself.
The follow-up study, published in the August issue of the Journal of the American Dietetic Association, confirms their initial hunch.
"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. 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 behavior," said Kristal, associate head of the Cancer Prevention Program in the Public Health Sciences Division at the Hutchinson Center.
The researchers found 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 researchers also 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.
"These findings fit with our hypothesis that yoga increases mindfulness in eating and leads to less weight gain over time, independent of the physical activity aspect of yoga practice," said Kristal, who is also a professor of epidemiology at the University of Washington School of Public Health.
Kristal, a yoga enthusiast for the past 15 years, said that yoga cultivates mindfulness in a number of ways, such as being able to hold a challenging physical pose by observing the discomfort in a non-judgmental way, with an accepting, calm mind and focus on the breath. "This ability to be calm and observant during physical discomfort teaches how to maintain calm in other challenging situations, such as not eating more even when the food tastes good and not eating when you're not hungry," he said.
To test whether yoga in fact increases mindfulness and mindful eating, Kristal and colleagues developed a Mindful Eating Questionnaire, a 28-item survey that measured a variety of factors:
- 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.
Each question was graded on a scale of 1 to 4, in which higher scores signified more mindful eating. The questionnaire was administered to more than 300 people at Seattle-area yoga studios, fitness facilities and weight-loss programs, among other venues. More than 80 percent of the study participants were women, well-educated and Caucasian, with an average age of 42. Participants provided self-reported information on a number of factors, including weight, height, yoga practice, walking for exercise or transportation and other forms of moderate and strenuous exercise.
More than 40 percent of the participants practiced yoga more than an hour per week, 46 percent walked for exercise or transportation for at least 90 minutes per week and more than 50 percent engaged in more than 90 minutes of moderate and/or strenuous physical activity per week.
The average weight of the study participants was within the normal range - not surprising considering that the study sample intentionally consisted of people more physically active than the U.S. population in general. Body-mass index was lower among participants who practiced yoga as compared to those who did not (an average of 23.1 vs. 25.8, respectively).
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," said Kristal, who himself scored high on the mindful-eating survey and has a BMI within the normal range.
Moving forward, Kristal and colleagues suggest that their Mindful Eating Questionnaire, the first tool of its kind to characterize and measure mindful eating, may be useful both in clinical practice and research to understand and promote healthy dietary behavior.
"Beyond calories and diets, mindful eating takes a more holistic approach that can empower individuals to build positive relationships with food and eating, said first author Celia Framson, M.P.H., R.D., C.D., a former graduate student of Kristal's - and former yoga teacher - who now works with adolescents with eating disorders at Seattle Children's Hospital. "The Mindful Eating Questionnaire offers a new and relevant dimension for measuring the effectiveness of dietary behavior interventions. It also encourages nutrition and medical practitioners to consider the broad scope of behavior involved in healthy eating," she said.
Other authors on the paper included Denise Benitez, owner of Seattle Yoga Arts; Alyson Littman, Ph.D., an epidemiologist at the UW School of Public Health and Department of Veterans Affairs; Steve Zeliadt, Ph.D., of VA Puget Sound Healthcare; and Jeanette Schenk, R.D., a research dietitian in the Hutchinson Center's Cancer Prevention Program.
Fred Hutchinson Cancer Research Center funded the study.
At Fred Hutchinson Cancer Research Center, our interdisciplinary teams of world-renowned scientists and humanitarians work together to prevent, diagnose and treat cancer, HIV/AIDS and other diseases. Our researchers, including three Nobel laureates, bring a relentless pursuit and passion for health, knowledge and hope to their work and to the world. For more information, please visit fhcrc.org.