The goal of this study was to understand how different types of diet buddy systems affect diet success and outcomes related to dieting. Pairs of non-romantic cohabiting female dyads (i.e. roommates) were randomly assigned to one of the following three-week manipulations: (a) neither roommate dieted, (b) one roommate was assigned to a 1200-calorie/day diet and the other ate normally, (c) both roommates were assigned to a 1200-calorie/day diet. Both pre- and post diet, participants were weighted and measured, filled out psychological questionnaires, and provided two days of diurnal salivary cortisol samples. During the three-week manipulation period, participants who were assigned to diet recorded all calories consumed on each day. This study tested whether dieting in a pair would lead to improved diet outcomes in terms of adherence and weight loss, changes in psychological well-being, and changes in cortisol.
This study examined how dieting with a partner affects weight loss, diet adherence, psychological well-being, and cortisol.