The Transtheoretical Model (TTM) postulates that change is a process that unfolds over time through a series of stages: Precontemplation, Contemplation, Preparation, Action, Maintenance, and Termination. The TTM is also based on critical assumptions about the nature of behavior change and population health interventions that can best facilitate such change. One potential is for TTM to treat multiple behaviors in a population since most populations have multiple behavior risks and are at risk for both chronic disease and premature death. Critics of the TTM have several core concerns. These include how well TTM constructs predict outcomes compared to non-TTM variables and whether TTM constructs predict progress across stages of change in the way that TTM should predict. Historically, studies conducted on multiple behavior changes have been limited by reliance on the action-oriented treatment and the lack of applying the most promising interventions, such as interactive and individualized TTM-tailored interventions.