Obesity remains a largely refractory threat to health in our population. Behavior modification and primary prevention through early inculcation of prudent dietary habits have largely failed to address the significant minority of the population with morbid obesity. Effective management for these patients has entailed some surgical alteration of gastrointestinal function to either mechanically restrict excess caloric intake or induce malabsorption. It seems inevitable that these surgical lesions will be applied for the foreseeable future since no other effective tactics are available. Therefore, a full understanding of the abnormalities caused by surgical modification of digestion should be sought to minimize side effects while retaining the objective of adequate nutrition and sustained weight loss.
The first major effort to induce malabsorption was the jejunoileal bypass that shunted luminal contents 35 cm beyond the ligament of Treitz into the last 10 cm of ileum, effectively bypassing the majority of the absorptive function of