Proposed is a 6-month randomized controlled trial, in 200 overweight or obese Stage I-IIIC breast cancer survivors examining 6-month changes in: 1) body weight, 2) diet, 3) physical activity, and 4)quality of life in women randomized to receive the modified LEAN intervention compared to women randomized to wait-list control (i.e., the wait-list control will receive the modified LEAN intervention after completing the 6-month study).