The cardioprotective effects of intensive lifestyle regimens in primary prevention have been elucidated; however, there is a paucity of data comparing the effects of different lifestyle regimens in patients with established coronary artery disease (CAD) or CAD equivalent, specifically vis-à-vis carotid plaque regression. We performed a randomized, single-center, single-blind study in 120 patients with established CAD. Patients were randomly assigned to either 9 months of the Complete Health Improvement Program (CHIP), an outpatient lifestyle enrichment program that focuses on improving dietary choices, enhancing daily exercise, increasing support systems, and decreasing stress; or to 9 months of an ad hoc, nonsequential combination of various healthy living classes offered separately through a health maintenance organization and referred to as the Healthy Heart program. Baseline and 9-month change in carotid intima-media thickness (CIMT) were measured. Among 120 participants, data were analyzed for 79, of which 68 (86%) completed the study. Both average CIMT and average maximum CIMT increased over 9 months, but the changes between groups were insignificant. There were marked differences in the mean body mass index favoring the CHIP group (-1.9 [standard deviation = 1.9]; p < 0.001) and statistically significant within-group improvements in blood pressure, triglyceride level, 6-minute walk test result, self-assessment well-being score, and Patient Health Questionnaire-9 score that were not observed between groups. Neither the CHIP nor Healthy Heart was effective in inducing plaque regression in patients with established CAD after a 9-month period. However, both were effective in improving several CAD risk factors, which shows that the nonsequential offering of healthy lifestyle programs can lead to similar outcomes as a formal, sequential, established program (CHIP) in many aspects. These results have important implications as to how lifestyle changes will be implemented as tertiary prevention measures in the future.