Bariatric surgery evolution from the malabsorptive to the hormonal era.

While bariatric procedures continued to evolve and develop since the 1950s, their classification has not matched this evolution. The procedures are commonly classified into restrictive, malabsorptive, or combined. In this day and age, we recognize different mechanisms of action of the bariatric procedures. This article aims to review and update the old classifications based on our current understanding of the hormonal aspects of the various bariatric procedures and the role of gut hormones in weight loss and treatment of the associated metabolic comorbidities. The article suggests the need for a new classification of the bariatric procedures, based on the mechanism of action, involving the hormonal aspects of the procedure.