This study is a randomized trial in which obese men and women are assigned to one of two study conditions, Standard Behavior Treatment (SBT) or Maintenance-Tailored Treatment (MTT). The MTT has adaptation to change as its central theme. A primary technique that is used to convey this theme that is different than traditional behavior treatment is that participants are asked to deliberately change weight-loss strategies systematically over time rather than to use the same approach consistently across time. Frequent change serves as a platform for teaching a larger variety of weight-control skills and thus strengthening study participants ability to adapt their weight-control strategies to changing circumstances. Changing weight-control strategies regularly also helps to reduce the extent to which habituation to strategies implemented invariantly over time diminish the salience of behavioral cues and the potency of behavioral reinforcers for sustaining weight-control efforts over time. Individuals in both treatment groups receive active intervention for a period of 18 months, followed by 12 months of no-treatment follow-up.