OBJECTIVES: Long-term results of dietary and behavioral treatment of obesity fail to match the obese patients' expectations, as well as the professionals' requirements. The therapeutic challenge remains to induce behavioral changes during treatment which are maintained over a long period of time, thus enabling long-term weight maintenance. The paper develops a framework to improve lasting behavioral changes. RESULTS AND CONCLUSIONS: Four elements may enhance long-term success. First, patients' unrealistic expectations about the weight loss have to be modified and patients have to be supported in accepting moderate and modest weight losses as success. Second, behavioral change can only be achieved if treatment involves a long-lasting training process, which for most patients needs to continue more than a year. Third, behavioral and attitudinal change should be governed by the principle of flexible control of eating behavior, and rigid control should be discouraged. Forth, long-term success appears to be more likely, the more behavioral dimensions are involved in the process of behavioral change.