To identify patterns of behavioral adherence among 388 African Americans who participated in the Weight Loss Maintenance trial and examine associated psychosocial factors. Using repeated measures latent class analysis, we modeled patterns of adherence to recommendations regarding fruit and vegetable, total fat, and saturated fat intake and physical activity at baseline, 6, and 18 months. Latent classes were compared on the SF-36 (mental health composite and vitality subscale), Perceived Stress Scale, and PHQ-8 at each time point. Three distinct latent classes emerged: Nutrition Adherers (n = 96); Physical Activity Adherers (n = 61); and Non-Adherers (n = 231). All groups showed initial improvement in psychosocial measures followed by relapse. Non-Adherers had significantly lower mean mental health and vitality scores and higher depression scores than adherers at 6 and 18 months. Psychological well-being should be addressed with African Americans in weight loss treatment to enhance behavior change and improve weight loss outcomes.