Engagement in online social network-delivered weight loss interventions is a predictor of weight loss. Incentivizing engagement in a subset of participants may increase group engagement and subsequent weight loss. In a pilot feasibility trial, 56 adults with obesity were randomized to two Facebook-delivered weight loss interventions, one had 10% users incentivized to engage daily and the other did not. We compared conditions on engagement and weight loss, and then compared incentivized users and natural high engagers on weight loss. Participants were 46.3 (SD: 10.3) years and 89% female. The incentivized user condition had greater total engagement (p=0.0361), but weight loss did not differ (p=0.2096). Three natural superusers emerged in each condition. Natural superusers lost more weight than incentivized users (p=0.0358). Natural superusers’ posts elicited more comments than incentivized superusers (p=0.0107). Incentivized superusers may engage differently than natural superusers. Future studies should explore ways to promote engagement in online interventions.