Associations Between Food Restriction, Alcohol and Marijuana Use and Co-Use, and Consequences Among College Students.

Background: Simultaneous alcohol and marijuana use (SAM) and food restriction on days students intend to drink are associated with an increased risk of substance use-related consequences. However, these negative outcomes have been studied mostly in alcohol-only use contexts. Little is known about the combination of alcohol, marijuana, SAM, and food restriction. Therefore, the current cross-sectional study investigated whether alcohol, marijuana, or SAM use and food restriction on substance use days were associated with an increased risk of negative substance-use outcomes.

Method: 901 college students completed a survey about their substance use and eating behaviors. Hierarchical regression analyses tested the relations between these patterns and use-related consequences.

Results: Among past 30-day alcohol users, alcohol use quantity and food restriction on substance use days independently associated with greater alcohol use consequences. Past 30-day frequency of food restriction on alcohol use days moderated the effect between average drink quantity and alcohol use consequences. Among past 30-day marijuana users, number of hours high and food restriction on use days independently associated with greater marijuana use consequences. For past 30-day SAM users, alcohol use quantity on SAM days significantly associated with greater alcohol consequences. Food restriction on SAM days moderated the effect of marijuana use quantity (i.e., number of times used) on marijuana use consequences.

Conclusions: These results provide the basis for further exploration of food restriction and SAM, as well as targeted interventions among at-risk populations.