title: Development and Efficacy Testing of a Social Network-Based Competitive Application for Weight Loss.
abstract: Although a lot of people continuously try to lose weight, the obesity rate has remained high: 36.9% of males and 38.0% of females worldwide in 2013. This suggests the need for a new intervention.
  
  
  
  In this study, we designed a smartphone application, With U, to aid weight loss by using an offline social network of friends and an online social network, Facebook. To determine the effects of With U, this study was designed as a one-group pretest-posttest design. Overweight, obese, and severely obese adults 20-40 years old, along with their friends, participated in this study. A total of 10 pairs attempted to lose weight for 4 weeks. We used a questionnaire to measure general characteristics, motivation, and intent to continue to use With U, and the Inbody720 (Biospace, Seoul, Republic of Korea) body composition analyzer was used to measure physical characteristics. In addition, we briefly interviewed the participants about their experience.
  
  
  
  We observed statistically significant effects in terms of motivation to lose weight and the amount of weight loss. Changes in physical characteristics beyond weight loss also showed positive trends. Also, we discovered some interesting facts during the interviews. The weight loss effect was greater when the team members met more and the relationship between the challengers was more direct and intimate.
  
  
  
  The application With U, designed and developed to allow friends to challenge each other to lose weight, affected both motivation to lose weight and the amount of weight loss. In the future, effects of smartphone applications for health management with social networks need to be studied further.
authors.affiliation: 1 College of Nursing, Seoul National University , Seoul, Republic of Korea.|2 Interdisciplinary Program of Medical Informatics, Seoul National University , Seoul, Republic of Korea.
authors.forename: Jisan
authors.initials: J
authors.lastname: Lee
authors.affiliation: 1 College of Nursing, Seoul National University , Seoul, Republic of Korea.|2 Interdisciplinary Program of Medical Informatics, Seoul National University , Seoul, Republic of Korea.|3 Research Institute of Nursing Science, Seoul National University , Seoul, Republic of Korea.
authors.forename: Jeongeun
authors.initials: J
authors.lastname: Kim
mesh_terms: D000328:Adult; D001837:Body Weights and Measures; D005260:Female; D006801:Humans; D008297:Male; D063731:Mobile Applications; D009042:Motivation; D009765:Obesity / Q000523:psychology / Q000628:therapy; D050177:Overweight / Q000523:psychology* / Q000628:therapy*; D056910:Republic of Korea; D060756:Social Networking; D012944:Social Support; D061217:Weight Reduction Programs / Q000379:methods*; D055815:Young Adult
keywords: game care; mobile health; smartphone application; social network; weight loss