Reversing Obesity: Clinical Trials of Yoga Interventions

By: Sandeep (Anu) Kaur, MS, RDN, RYT-500 and Sat Bir Singh Khalsa, PhD

Obesity, an important modifiable risk factor associated with chronic disease, is at epidemic levels in the U.S. with an expected 40 percent increase worldwide by 2030. The rise in obesity is associated with a sedentary lifestyle, dietary choices often high in calories, fat, and sugar, and stress-induced changes in psychophysiology and eating-related behavior. Traditional weight loss strategies focus on dietary changes and exercise which often result in only short-term weight loss that is ultimately regained. These weight loss approaches typically do not address the role of stress in obesity and do not appear to lead to long-term lifestyle behavior change that is necessary for weight maintenance. The rationale for yoga as an intervention for weight loss is that it is a multicomponent intervention targeting multiple physical, psychological, and behavioral factors. Although more intensive physical yoga exercises and postures result in higher energy expenditure, research studies suggest yoga goes beyond energetics. Yoga practice additionally provides positive changes in breath regulation, stress and emotion regulation, mind-body awareness, mindfulness, and even life purpose and meaning, all of which contribute to addressing the key factors in obesity. Hence, it is not surprising that a number of clinical research trials of yoga interventions have been conducted on obese patients.

One of the earliest research trials by Gharote and colleagues (1977) in India evaluated the effects of yoga on obesity via skinfold measurement and estimated body fat. They found a significant reduction in estimated body fat percentage in both men and women after two months of yoga treatment, paving the way for further studies of yoga and obesity as well as other lifestyle diseases such as diabetes. Divekar and colleagues (1978) reported decreased blood glucose and weight loss in individuals with chronic diabetes who practiced yoga outdoors for 45-minutes once a day and utilized slow and rhythmic contraction of muscles and deep slow breathing. Venkatareddy and colleagues (2003) also evaluated the impact of yoga asana and pranayama (breath techniques) on 30 obese Indian women who continued with their regular diet for three months. They too noted a significant reduction in weight and estimated body fat percentage at the end of 30 and 90-days. From the results of these early Indian randomized control trials (RCTs) it was hypothesized that yoga induces hypothalamic changes and conditioned the autonomic nervous system via the hypothalamus to influence other endocrine functions including insulin regulation. In another Indian yoga trial, Bera and colleagues (2003) randomly assigned 153 obese patients to either yoga training in a residential setting (consuming a pure vegetarian diet), a non-residential setting (subjects stayed at home on their usual diet) or a no-treatment control group. The researchers found a significant reduction in anthropometrics such as body weight, hip girth, body fat, and abdominal girth along with increased muscular strength and flexibility in the residential group compared to the other two groups. The authors concluded that yoga may be a more easily accessible form of exercise that can improve impaired musculoskeletal functioning in obese patients.

In the U.S., few residential multi-component yoga-based weight loss programs have been conducted. Braun and colleagues (2012) at the Kripalu Center for Yoga & Health evaluated a 5-day weight loss program that incorporated yoga, mindfulness, self-compassion, acceptance, non-dieting, and intuitive eating to promoted long-term weight loss. 37 participants, primarily Caucasian women, middle-aged, with high levels of education and income, and 84 percent classified as obese (Body Mass Index [BMI]  30), participated in the study. Although physical activity and mood disturbance improved significantly post-program, they did not reach significance at the 3-month follow-up, even though self-reported weight loss was statistically significant at the one-year follow-up. This study points to the potential of a yoga-based approach for obese individuals to foster well-being, stress management, mind-body awareness, improve nutrition choices, eating behavior, and to provide support for a deeper lifestyle change.

Other studies have been starting to look at the impact of in-house residential yoga weight loss programs that include yoga philosophy and Ayurvedic-inspired daily living strategies. Rioux and colleagues (2014) conducted a feasibility study with 12 women to evaluate a weight loss program based on principles of Ayurveda and yoga therapy with an emphasis on self-monitoring of lifestyle behaviors. Participants completed 75-minute supervised yoga classes three times a week and did the yoga practice an additional three times at home per week. There was a 7.1 kg difference between those who followed the program and those who did not. They also reported improved self-efficacy for exercise and diet change at long-term follow-up and improved energy, well-being, quality of life, and self-awareness. In another investigation, Braun and colleagues (2016) also evaluated the effectiveness of an Ayurveda-inspired weight management curricula with both yoga-experienced and yoga-naïve women. This novel pilot revealed improved self-reported psychosocial factors such as mindful eating and body image in both overweight/obese yoga-naïve and yoga-experienced women. These preliminary data suggest that group-based yoga weight management programs that include yoga and Ayurvedic lifestyle principles may help with weight maintenance.

More recently, Cramer and colleagues (2016) in Germany looked at the effect of yoga on abdominal circumference and other anthropometrics in 60 women with an abdominal circumference  35 inches and BMI  25 who were randomly assigned to either a 12-week yoga intervention or a no-treatment control. The researchers observed a significant reduction in waist circumference with the yoga intervention group compared to the untreated control group in addition to positive effects with the yoga intervention on anthropometric measures such as reduced waist-hip ratio, body weight, BMI, and percentage of body muscle. Yoga also improved participants self-reported mental and physical wellbeing, self-esteem, and perceived stress.

Overall, a review of the literature on yoga for weight loss in obese individuals postulate that enhanced awareness brought on by yoga leads to healthier food choices, slower and more mindful eating, and ultimately healthy body mass index. A major limitation of the RCTs were the small sample sizes and the limited methodology reporting on specific yoga techniques used. In a comprehensive meta-analysis on RCTs done for yoga and weight management, an analysis of 30 published research trials with a total of 2,173 participants indicated that yoga was considered a safe and effective intervention to reduce BMI in in otherwise healthy adults who were overweight or obese. Key factors that may play a role in yoga’s effectiveness in weight loss and maintenance are duration of practice, frequency, dietary elements, and the residential or home practice aspect.

In summary, the research published to date suggests that yoga can be an acceptable, safe, noninvasive, low-risk, and effective treatment option for obesity, reducing BMI and other anthropometric measures in obese or overweight adults. Importantly, yoga appears to affect key underlying risk factors including stress, emotion, mind-body awareness, and overall lifestyle behaviors. Additionally, the efficacy of yoga may possibly be supplemented and enhanced by interventions in residential treatment settings and by the additional incorporation of Ayurveda. Future yoga research with stronger research protocols will offer clarity and possibly confirm these preliminary findings that yoga can play an important role in the successful long-term treatment of obesity. An example of an ongoing trial in this direction is a comprehensive, country-wide study of yoga for obesity in India by the Patanjali Research Foundation led by yoga researcher Shirley Telles with a proposed sample size of 7,000 participants measuring anthropometric, biochemical, and psychological outcomes with a long-term, one-year follow-up.

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