Contingency Management for Promoting Weight Loss in University Students

Rates of overweight and obesity are increasing, particularly among individuals aged 18 to
29. An estimated 25-35% of American college and university students are overweight or obese.
Contingency Management (CM) is a behavioral intervention that provides tangible rewards for
positive behaviors. CM has substantial evidence of efficacy in reducing smoking and drug use
and increasing treatment retention and medication compliance. The current study will
evaluate the efficacy of a 24-week CM intervention to promote weight loss in overweight and
obese university students. Seventy participants with a body mass index (BMI) of 27.0-34.9
will be randomly assigned to one of two conditions: (a) LEARN, a manual guided behavioral
weight loss program (Brownell, 2004), with weigh-ins and supportive counseling, or (b) LEARN
with weigh-ins and supportive counseling plus CM. Participants in the CM condition will earn
chances to win prizes each week in which they lose at least one pound. Once they lose 5% of
baseline body weight, they will earn chances to win prizes for weight loss or weight
maintenance. Additional chances can be earned by completing activities that promote weight
loss. The primary outcomes will be absolute and proportional weight loss from pre- to
post-treatment, as well as proportion of participants achieving clinically significant
weight loss (>5% of baseline weight) and proportion moving into a lower risk BMI category.
Secondary outcomes will include length of retention in the study, increase in physical
activity level, and improvement in nutritional quality of diet. Effects of the CM
intervention on psychiatric distress and self-efficacy and motivation to engage in
activities that promote weight loss will also be assessed. We predict that participants in
the CM condition will lose more weight than participants assigned to the LEARN program
without CM, and that more CM participants will achieve clinically significant weight loss.
We also predict that participants in the CM condition will remain in the program longer,
show larger increases in physical activity, show greater improvements in diet quality, and
have greater increases in levels of self-efficacy and motivation than comparison group
participants. Mediators and moderators of CM outcomes will also be evaluated. If efficacious
in promoting weight loss in a college population, CM could help to prevent or delay later
development of obesity-related medical problems.