This is a randomized study comparing the efficacy of inducing weight loss of two treatment arms all based on the Colorado Diet. Subjects will be randomly assigned to one of two study arms and instructed to follow the Colorado Diet by participating in weekly State of Slim group classes. Subjects will be followed in the study for one year. The Colorado Diet consists of 3 phases: phase 1 (week 1-2), phase 2 (weeks 3 - 8), and phase 3 (weeks 9 - 16). The maintenance phase lasts from months 5 - 12. Body weight will be monitored at each study visit and body composition will be determined using DXA. Blood lipid and lipoprotein concentrations, health \& wellness questionnaires, and fitness measures will also be assessed throughout the study.