Weight loss competitions at the worksite: how they work and how well.

Three studies were conducted to evaluate the effectiveness of competition as a method of weight loss at the worksite. Study 1 found team competitions more effective than either cooperation or individual competition for men, and more effective than individual competition for women. Study 2 replicated the effectiveness of team competitions at 10 worksites. The influence of four variables [gender, age, type of employment (blue-collar vs white-collar), and method of assignment to teams] upon four outcomes (recruitment, attrition, weight loss, and cost/effectiveness), was assessed. This study showed that the results of competition were robust and widely generalizable. Recruitment was high, attrition very low, weight losses large, and cost/effectiveness favorable. Study 3, however, found only limited maintenance of weight loss following competitions.