This article explores the surprising finding that bariatric surgery can produce full and durable remission of the metabolic syndrome as well as other comorbidities of obesity including type II diabetes, hypertension, polycystic ovary syndrome, gastroesophageal reflux disease, nonalcoholic steatotic hepatitis, adult asthma and improvement in weightbearing arthropathy. Such an outcome was previously deemed impossible. One effect of the surgery is the correction of hyperinsulinemia, a common denominator in the various expressions of the metabolic syndrome. Basal insulin levels return to normal levels within a matter of days following surgery, allowing a return of the first phase of insulin secretion. This effect is ‘dose related’ to the extent of the reduction of contact between food and the gut. The resolution of the spectrum of diseases that comprise the metabolic syndrome following bariatric surgery suggests that hyperinsulinemia may be the common cause that is corrected by lowering contact between food and the gut. If this concept is true, then the cause of the syndrome, including diabetes, could be a diabetogenic signal from the gut that forces the islets to produce excessive and harmful levels of insulin, or the cause could be the removal of a signal that blocks exces-sive insulin secretion. If either of these mechanisms is proven correct, the current treatment of diabetes with long-term insulin administration deserves review.