Medical events that “trigger” motivation to lose weight may improve treatment outcomes compared to non-medical or no triggering events. However, previous findings include only long-term successful participants, not those initiating treatment. The current study compared those with medical triggering events or non-medical triggering events to no triggering events on attendance and weight loss during a weight management program. Medical-triggering-event participants lost 1.8 percent less weight (p = 0.03) than no-triggering-event participants. Non-medical-triggering-event participants attended 1.45 more sessions (p = 0.04) and were 1.83 times more likely to complete the program (p = 0.03) than no-triggering-event participants. These findings fail to support the benefit of medical triggering events when beginning treatment for obesity.