Weight-loss surgery has been shown to contribute to the improved health and well-being of the clinically severe obese, and for many has been seen as their "last resort." Although the majority of patients who choose this option as a means to achieve a healthier weight are successful, for some patients it is not beneficial. Bariatric surgery is not a panacea, and its immediate and long-term success depends on the patient's ability to incorporate lifestyle and behavioral changes. Patients who are not successful in achieving and maintaining their anticipated weight loss struggle to comply with diet, exercise, and vitamin regimens. Not only do these patients exhibit diminished weight loss, they have put themselves at risk for vitamin and mineral deficiencies and protein malnutrition. Their problematic response to weight-loss surgery may or may not be due to a worsening of presurgical depression, binge eating, emotion-triggered eating, body image, or eating behaviors associated with specific situations such as social events. This paper describes clinical responses we have observed in our bariatric practice. Several case studies are presented to highlight problems we have encountered when following bariatric surgery patients in the early postoperative period, as well as in a long-term setting. Recommendations are made for screening and follow-up of at-risk patients.