This study indicates that following SG, the stomach empties its contents rapidly into the small intestine and symptoms of vomiting after eating (characteristic of restrictive procedures) are either absent or very mild. Therefore, the term 'restrictive' is possibly ill-advised for this new bariatric operation. It remains for other mechanisms of energy intake reduction, such as intestinal distension and satiety signals through gut hormones to be investigated, to comprehensively explain precisely how this 'food limiting' procedure results in weight loss.

Our study indicates the constant effect of SG in the acceleration of gastric emptying of solids, which occurs faster, not only in short but also in long-term postoperatively. Such effects on gastric motility, in combination with the reported alterations in gut hormones, may explain how this 'food limiting' operation results in weight loss.

The BIB served as a first step and a smooth introduction to bariatric surgery for morbidly obese patients who initially refused surgical intervention. The incidence of surgical intervention was double in patients who initially experienced the benefits of weight loss and then had obesity recurrence, compared with patients in whom the method failed. Indeed, a significant number of patients were assisted in their efforts to lose and maintain an acceptable weight loss over a 6- to 30-month follow-up period.

Randomised controlled trials (RCTs) do not exist on this issue but the available observational evidence does suggest that RBS is associated with generally good outcomes similar to those experienced after primary surgery. Further, high-quality research, particularly RCTs, is required to assess long-term weight loss, comorbidity and quality of life outcomes.

LSG markedly improved glucose homeostasis and generated significant changes in ghrelin, PP, PYY, GLP-1, amylin, and leptin levels. These multiple hormonal actions may have several beneficial effects on the underlying mechanism of weight loss, demonstrating that LSG could be more than just a restrictive bariatric operation.