Obesity is one of the top health issues around the globe. Rapid adoption of smartphones presents an opportunity for delivering technology-based interventions that are designed to tackle behaviors that contribute to weight gain. Research shows that the vast majority of weight loss apps in the market place do not go beyond deploying tracking based strategies that are burdensome to the users. In this study, we present a new mobile app and an intervention system called SlipBuddy that puts less burden on users and implements stimulus control strategy to help users lose weight. We describe the SlipBuddy system in detail and present the results of the first phase of a pilot study. Our findings indicate that a mobile app that simply helps users identify and track overeating episodes can potentially result in weight loss.