Engagement in health-related behaviors is highly complex and influenced by a multitude of individual- and environmental-level factors. In addition, health-related behaviors tend to co-occur, or cluster, which adds to their complexity and presents challenges for health promotion and public health prevention efforts that may affect interrelated behaviors in different ways. This case study describes research exploring clustering of dieting with other health-compromising behaviors among adolescent girls. Dieting is of interest because it is highly prevalent among this population and has negative implications for physical and mental health, with prior evidence suggesting that it heightens risk of engaging in other risky behaviors. Drawing upon secondary data from the Cohort study on Obesity, Marijuana use, Physical activity, Alcohol use, Smoking, and Sedentary behavior (COMPASS), a Canadian school-based study, we examined cross-sectional and longitudinal associations between dieting and clusters of other behaviors, including smoking, binge drinking, and breakfast-skipping. The design of the study and the strengths and limitations of projects leveraging secondary data are detailed. Subsequently, we describe the process of selecting variables of interest, finalizing the analytic sample, operationalizing the variables and specifying regression models, and interpreting the results. Challenges encountered in planning and conducting this research are highlighted to inform similar projects. This case provides a unique demonstration of how health-related behavioral clusters can be explored, providing a foundation to deepen our understanding of the complexity of health behaviors and the implications of this complexity for efforts to support health.