Caffeine is an accessible, frequently--used psychoactive substance among college students. Particularly relevant among individuals with eating disorder symptoms are caffeine’s physiologic effects, which may suppress appetite, increase metabolism, and delay muscle fatigue following exercise. Further, caffeine intake may be uniquely appealing to individuals with eating disorders, as it is found in beverages that often contain few calories (e.g., black coffee).

While those with eating disorder symptoms use caffeine similarly to non-eating disorder samples in terms of overall consumption, the pattern of consumption among those with eating disorder symptoms is markedly different. Specifically, among individuals with anorexia nervosa and bulimia nervosa, caffeine use is associated with increased vigilance and attention to dietary intake, in addition to the using caffeine to suppress appetite.

The purpose of this research project is to test the effect of caffeine and expectancies involving the effects of caffeine on appetite on the link between restraint (i.e., the intention to restrict food intake) and restriction (the actual limiting of intake).

This study is comprised of three visits, one baseline and two experimental visits where either a placebo pill or 200mg caffeine pill is administrated (in a double-blind procedure). The primary task of the study is a computerized math-task. Depending on the accuracy of the participants responses, they will either be given access to drink zero-calorie Kool-Aid or high-calorie Kool-Aid. The motivation to persist at the task and avoid drinking the high-calorie mixture measures restraint. Participants complete this task at all three visits to determine if there is a significant statistical difference between baseline, placebo, and caffeine, which may indicate a meaningful caffeine expectancy effect.