Yoga in women with abdominal obesity - Do lifestyle factors mediate the effect? Secondary analysis of a RCT

Introduction: The reduction of obesity is an important challenge for health policy. Although dietary interventions are widely available, patient adherence is usually low. A promising alternative is yoga. We hypothesized that weight reduction through yoga is mediated by aspects related to eating habits as well as physical aspects. Methods: This is an exploratory secondary analysis of a randomized controlled trial comparing the effects of yoga to waiting list in women with abdominal obesity. Body mass index (BMI) and waist circumference were assessed as outcomes; physical exercise habits, physical activity habits at leisure time, physical activity habits at work time, daily fruit and vegetable intake, nutrition self-efficacy, and physical self-efficacy were captured as mediators. Measures were assessed at weeks 0 and 12. The original trial was conducted between April and August 2015. The secondary analysis was performed December 2019. Results: Forty patients were randomized to the 12 weekly yoga sessions (48.5 +/- 7.9 years) and 20 patients to the waitlist group (46.4 +/- 8.9 years). Physical exercise habits fully mediated the effect of yoga on BMI (B=-0.26;CI [- .56;- .07]). Daily fruit and vegetable intake partially mediated the effect of yoga on BMI (B=-0.13;CI [-.38;-.01]). No further mediation effects were found. Conclusions: Yoga supports people with overweight in eating healthier and increasing their physical activity which in turn leads to a reduced BMI. Yoga's effects on waist circumference seem to be due to other mechanisms.