Obesity and overweight affect more than two-thirds of adult Americans, increasing their risk for heart disease, stroke, type 2 diabetes, and certain cancers. The estimated annual medical cost of obesity in the United States was $147 billion in 2008, according to the CDC. While more and more evidence links chronic stress with obesity, effective strategies for managing stress in obesity are lacking, says Nazia Raja-Khan, MD. Mindfulness-based stress reduction (MBSR) has been shown to reduce subjective stress in various patient populations, but its impact on cardiometabolic outcomes in patients with obesity are unclear.
To determine the feasibility and cardiometabolic effects of MBSR in women with overweight and obesity, Dr. Raja-Khan and colleagues conducted a randomized controlled trial of women with a BMI of 25 kg/m2 or greater. Published in Obesity, the study randomized participants to 8 weeks of MBSR or health education (control group) and followed them for 16 weeks. The two participant groups were similar in age, BMI, and other baseline characteristics. The study’s primary outcome was the Toronto Mindfulness Scale (TMS), and secondary outcomes included subjective stress, fasting glucose, and blood pressure.
MBSR consisted of instructor-led, weekly 2.5-hour sessions for 8 weeks and a 6-hour retreat session, with participants asked to do 25 to 30 minutes of daily home practice. Patients in both groups were provided the same written guidelines on diet and exercise. However, the health education group received additional diet and exercise information through instructor-led, weekly, 2.5-hour sessions for 8 weeks and a 6-hour retreat.
Multiple Benefits With MBSR
Among participants, 71% and 62% completed the 8- and 16-week follow-up visits, respectively. Those in the health education group had a significantly higher dropout rate at 8 weeks when compared with the MBSR group. In regard to outcomes, “MBSR significantly increased mindfulness and reduced subjective stress when compared with health education,” says Dr. Raja-Khan (Figure). In fact, mindfulness increased 19% from baseline to 8 weeks for those in the MBSR group, leading to significant between-group difference of 5.4 in change in TMS total score. However, significance was not sustained at 16 weeks.
“Fasting glucose significantly decreased at 8 weeks and at 16 weeks when compared with baseline in the MBSR group, but not in the control group,” adds Dr. Raja-Khan. “In both groups, the changes in weight were small (0.8 kg) and not clinically or statistically significant. The reduction in fasting glucose compared with baseline was statistically significant in the MBSR group only. The reduction in fasting glucose in the health education group was not clinically or statistically significant. The reason for the reduced fasting glucose in the MBSR group remains unclear. There were no changes in weight, cortisol, or insulin resistance to explain the reduction in glucose. One possible explanation is that the increased mindfulness could have made it easier for the MBSR group to adhere to a lower carbohydrate diet or exercise regimen.”
Dr. Raja-Khan notes that future studies are needed to determine if sustained increases in mindfulness with a more long-term MBSR intervention will have a greater impact on obesity, diabetes, and other chronic diseases that have been linked with stress. “Future studies should also evaluate whether changes in diet and exercise explain the improvement in glucose with MBSR,” she adds. “Finally, as our study population only included women, future studies will need to confirm our findings and determine whether they are generalizable to both men and women. If future studies confirm that MBSR lowers glucose in people with overweight or obesity, then MBSR could be an effective adjunctive tool for preventing or treating type 2 diabetes.”
In the meantime, Dr. Raja-Khan says that it is important for physicians to recognize that stress may adversely impact the health of their patients, particularly those with chronic diseases such as obesity and diabetes.