Dietary Modification
Conditions
Keywords
dieting, dyads, psychological well-being, weight loss, cortisol
Brief summary
This study examined how dieting with a partner affects weight loss, diet adherence, psychological well-being, and cortisol.
Detailed description
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.
Interventions
BEHAVIORALMixed Diet Condition
One roommate dieted and the other ate normally.
BEHAVIORALBoth Diet Condition
Both roommates dieted.
Sponsors
A. Janet Tomiyama
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Female * Over 18 years of age * Interested in dieting in the coming 12 months * self-reported BMI over 18.5 * \< 5 kg weight change in previous 3 months * Have a university meal plan * Have a roommate also willing/eligible to participate
Exclusion criteria
* Recent/current history of major medical disorder * Pregnancy/lactation * History of eating disorder * Use of lipid-lowering medications * Use of weight-altering/metabolism-altering medications * Smoking
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Psychological well-being measured via electronic questionnaires | ~3 days after end of 3-week manipulation |
| Weight loss measured via pounds | ~3 days after end of 3-week manipulation |
| Diet adherence measured via daily calorie counts | up to 3-week |
Secondary
| Measure | Time frame |
|---|---|
| Cortisol measured via 2 days diurnal cortisol | 1 day after end of 3-week manipulation |
Outcome results
None listed