The obesity epidemic is a pervasive health issue affecting all population groups in developed countries. The purpose of this research was to ascertain obesity risk reduction behaviors and their psychosocial determinants in young adult Americans residing in New Jersey state. A cross-sectional survey design was implemented in which a convenience sample of 174 participants (18 to 40 years) completed a validated online self-administered questionnaire. Nineteen obesity risk reduction behaviors, self-efficacy and psychosocial constructs derived from the Theory of Planned Behavior were measured. Statistical analyses were conducted using frequency distributions, t-tests and regression analysis. Regression analysis indicated that 37.5% of the variance in obesity risk reduction behavior was accounted by self-efficacy alone. T-test comparisons indicated greater frequency of adoption of 17 health behaviors among individuals categorized in the 'high self-efficacy' group (p<0.05). These behaviors included limiting portion sizes of food, eating fruits and vegetables, engaging in physical activity, and monitoring stress and body weight. Nutrition professionals working with young adult Americans need to assess their self-efficacy to engage in obesity risk reduction behaviors. In fostering confidence in adopting these behaviors, executing skill building nutrition interventions is critical for obesity prevention.