A Social-networking-site(SNS) Based Weight Loss Behavior Intervention- the Effect of Social Network and Multi-level Factors on Weight Loss

We plan to organize a private Facebook group serve as platform to provide the intervention content. To ensure confidentiality, this Facebook group is completely private and the group member is invited only by study staff. The participants of intervention group received information about the private Facebook group and privacy settings and were instructed to join the Facebook group. The intervention comprises three parts. Doctor patient interaction: The interventionist (physicians and dietitians) act as health coach will provide evidence-based topics related to weight loss on Facebook discussion board every two weeks

In the session, the participants are instructed by an interventionist to have a reduced calorie diet and regular physical activity. Calorie intake was prescribed based on baseline weight at 1200 kcal/d for individuals who weighed less than 90 kg, 1500 kcal/d for those who weighed 90 to less than 115 kg, and 1800 kcal/d for those who weighed 115kg or more. The interventionist will give each participants dietary recommendation and sample meal plans are provided to facilitate adoption. The interventionist will prescribe non-supervised moderate-to-vigorous physical activity to participants. Participants should start moderate-to-vigorous physical activity at 100 minutes per week and increased at 4-week intervals until a prescription of 300 minutes per week was achieved