This is a 3-arm randomized controlled trial to test the efficacy of three novel motivational approaches to weight loss with 18-25 year olds. Participants will be 18-25 year olds with a BMI of 25-45 kg/m2, randomized to: 1) Behavioral Weight Loss (BWL), 2) BWL + Autonomous Motivation (BWL+Aut) or 3) BWL + Extrinsic Motivation (BWL+Ext). All arms will receive a 6-month behavioral weight loss intervention, followed by a 6-month no-treatment follow up period.