Low glycemic index vegan or low-calorie weight loss diets for women with polycystic ovary syndrome: a randomized controlled feasibility study

The aim of this randomized pilot was to assess the feasibility of a dietary intervention among women with polycystic ovary syndrome (PCOS) comparing a vegan to a low-calorie (low-cal) diet. Overweight (body mass index, 39.9 ± 6.1 kg/m2) women with PCOS (n = 18; age, 27.8 ± 4.5 years; 39% black) who were experiencing infertility were recruited to participate in a 6-month randomized weight loss study delivered through nutrition counseling, e-mail, and Facebook. Body weight and dietary intake were assessed at 0, 3, and 6 months. We hypothesized that weight loss would be greater in the vegan group. Attrition was high at 3 (39%) and 6 months (67%). All analyses were conducted as intention-to-treat and presented as median (interquartile range). Vegan participants lost significantly more weight at 3 months (−1.8% [−5.0%, −0.9%] vegan, 0.0 [−1.2%, 0.3%] low-cal; P = .04), but there was no difference between groups at 6 months (P = .39). Use of Facebook groups was significantly related to percent weight loss at 3 (P < .001) and 6 months (P = .05). Vegan participants had a greater decrease in energy (−265 [−439, 0] kcal/d) and fat intake (−7.4% [−9.2%, 0] energy) at 6 months compared with low-cal participants (0 [0, 112] kcal/d, P = .02; 0 [0, 3.0%] energy, P = .02). These preliminary results suggest that engagement with social media and adoption of a vegan diet may be effective for promoting short-term weight loss among women with PCOS; however, a larger trial that addresses potential high attrition rates is needed to confirm these results.