Together, diabetes and cardiovascular disease cost the U.S. economy a staggering $557.6 billion annually and are the leading chronic diseases of African Americans. Maintaining a healthy body weight by being physically active and eating a healthy diet are the best means of reducing cardio-metabolic risk factors. Despite decades of behavioral research, however, lifestyle interventions targeting activity and diet have made little progress in effecting widespread and enduring health behavior changes in the populations most at risk for developing these conditions. Addressing the role of habits, defined as behavior patterns operating below conscious awareness that are acquired through context-dependent repetition, would significantly improve the effectiveness of lifestyle interventions. Most simply, habits develop when repetition of a behavior (e.g., walking for 10 minutes) occurs in connection with a stable situational cue that supports the behavior (e.g., while on a lunch break). Once established, habits are cued by the characteristics of a specified recurring situation rather than by intentions. Recent research suggests that habit development may prevent relapse and aid maintenance of behavior changes beyond the duration of the intervention because the performance of habitual behaviors is less vulnerable to changes in motivation, mood, or extraneous circumstances. Emerging evidence also suggests that habit-development strategies are (a) effective across a range of behaviors (e.g., dental flossing, physical activity, and dietary behaviors); (b) effective in low doses; and (c) deliverable via multiple formats (e.g., paper or electronic). Such strategies could therefore be feasibly implemented in a range of settings to target the development of healthful physical activity and dietary habits. Nonetheless, these concepts and methods have yet to be fully tested to determine their feasibility as a treatment modality for promoting healthful lifestyle behavior changes.