One hundred twenty applicants to a weight management specialist training program were studied over a 33-month period. Following a nine-month training period, Specialists (N = 29; those leading at least one posttraining weight management group) were compared to Contact Controls (N = 31; persons participating in the weight management program, but not in the helper role) and No Contact Controls (N = 60; those not accepted into the training program and whose only contact with the program was for data collection purposes) in a test of the helper-therapy principle. The major question was, "What are the long-term physical, psychological, and behavioral effects on overweight and formerly overweight individuals involved in helping other persons manage their weight?" Data gathered at 12 and 24 months post-training revealed few differences between the total group of specialists and persons in the two control groups. However, when the data were analyzed by the amount of commitment to the specialist role, it was found that the Higher Involved Specialists (N = 16; those who led two or more weight management groups in the year posttraining) were significantly more likely to lose additional weight (or maintain earlier weight losses), to be more consistent in their adherence to the eating and activity levels advocated by the program, to feel better about themselves and their bodies, and to maintain their levels of general well-being than control subjects or the Lesser Involved Specialists. These latter individuals (N = 13) were significantly the worse for having gone through specialist training, but not fully carrying out the specialist role.