Teammates and Social Influence Affect Weight Loss Outcomes in a Team-Based Weight Loss Competition

This article examines the impact of team-based interventions on weight loss during a statewide weight loss competition in Rhode Island. Previous research has suggested that social networks can affect weight and physical activity patterns and, therefore, team-based competitions might help achieve weight loss goals.

The authors studied Shape Up Rhode Island, a 12-week weight loss program that enrolled 3,330 obese and overweight individuals on 987 teams in 2009. Multilevel modeling examined how weight loss clustered among teammates and across different exercise regimes.

Key Findings:

  • Overweight and obese participants reported losing an average of 4.2 percent of body weight. One-third of participants who completed the program lost more than 5 percent of body mass.
  • Weight loss clustered within teams so that individuals whose teammates had greater weight loss were more likely to lose clinically significant amounts of weight.

These results suggest that individual weight loss was influenced by the weight loss of teammates. Weight loss programs that harness this team-based effect may help combat obesity and improve public health.