BACKGROUND: The prevalence of obesity has reached epidemic proportions in many countries and is largely due to behavioral factors that disrupt the energy balance. The purpose of the study was to test how well our conceptual model, combining features from the Theory of Planned Behavior and the Theory of Triadic Influence, explained two behaviors related to the energy balance, namely bicycle use for transportation and snacking behavior in a Dutch adolescent sample. METHODS: Data was gathered in an 1997 cross-sectional sample of adolescents (n = 3,859; mean age 14.8 years SD = 1.6) on snacking behavior, bicycle use, demographics, and potential environmental, cognitive and psychological determinants. Data was analyzed using bivariate correlations, multiple linear and binary logistic regression analyses. RESULTS: Less snacking behavior was associated with female gender and a more positive intention, a more positive attitude, and stronger perceived behavioral control towards restricting snacking. Students who used their bicycle for transportation were more likely to attend secondary education, to be native Dutch, to go to school in a less-urbanized city, to be younger, had a more positive intention and perceived stronger behavioral control and subjective norm towards bicycle use. CONCLUSIONS: The inclusion of environmental factors increased our understanding of bicycle use for transportation and snacking behavior in adolescents. The environmental factors are suggested to be taken into account in interventions aimed at changing these behaviors in more healthy directions.