Peggy O'Halloran, DeAnn Lazovich, Ruth E. Patterson, Lisa Harnack, Simone French, Sue J. Curry, Shirley A. A. Beresford

To examine the effect of lifestyle on the effectiveness of a low-intensity dietary intervention. A secondary data analysis was performed using data from the Eating Patterns Study, a randomized controlled trial that found that self-help materials with physician advice was effective in changing dietary intake and behavior. Primary care clinics in a large health maintenance organization. A total of 2111 patients with a routine scheduled appointment with their primary care physicians. Participants were grouped into one of six health lifestyle patterns based on similarities in baseline measures of alcohol intake, smoking, diet quality, and exercise. Within each lifestyle pattern, changes from baseline in usual fat and fiber intake (based on a food frequency) and a fat and fiber behavior score were compared at 3 months and 12 months for intervention vs. control participants. Self-help materials delivered by a physician with advice to change diet. Intervention participants in the fitness lifestyle group made the largest changes relative to controls for each dietary outcome at 3 and 12 months. For intervention participants defined by their alcohol intake or current smoking, either no changes in diet were observed compared with controls, or early changes were not sustained over time. Intervention-control comparisons within the remaining lifestyle patterns showed smaller dietary changes compared with the fitness lifestyle. This finding was similar to previously published results. This randomized controlled trial had limited power to detect subgroup differences; however, these results suggest that lifestyle patterns may be useful in the development of effective, targeted interventions to change behavior.