Using self-determination theory to understand eating behaviors and weight change in emerging adults

College may be a time when emerging adults establish eating patterns that influence future weight trajectories. Self-determination theory (SDT) suggests that satisfaction of basic psychological needs (autonomy, competence, relatedness) supports autonomous regulation of behavior, which is associated with healthier behaviors. When needs are frustrated, individuals feel as though their behaviors are controlled by others, which is associated with unhealthy behaviors. This study used SDT to examine a model for associated body satisfaction, eating/weight control behaviors, and weight change.

Using a cross-sectional design, undergraduates (N = 875; 57% women; Age_M = 20 ± 1.4 yrs.; BMI_M = 24.3 ± 4.4) completed measures of need satisfaction and frustration, behavioral regulation of healthy weight, body satisfaction, eating/weight control behaviors, and weight change in their first semester of college.

Structural equation modeling showed that need satisfaction was positively associated with greater autonomous regulation, which was positively associated with greater body satisfaction and fruit/vegetable intake. Conversely, greater need frustration was associated with greater controlled regulation, which was associated with lower body satisfaction. Participants who had greater body satisfaction engaged in fewer unhealthy weight control behaviors. Engaging in more unhealthy behaviors was associated with greater weight gain during the first semester of college, whereas fruit and vegetable intake was not associated with weight change. The associations were stronger for women than men, particularly for the relationships between body satisfaction and unhealthy weight control behaviors and increased weight gain.

The model was generally supported, suggesting that psychological need satisfaction and autonomous motivation in college students may facilitate greater body satisfaction and healthier eating behaviors. Future longitudinal research is needed to clarify the factors that influence health behaviors and weight gain in college students.