The incidence of diabetes among morbidly obese patients is over 25%. The most effective treatment for overweight people with type 2 diabetes is metabolic and bariatric surgery. About 80% of type 2 diabetic patients undergoing bariatric or metabolic surgery get rid of this disease without any need to use the medicine. Metabolic surgery changes the level of many hormones such as GLP-1 (glu**gon-like peptid-1), PYY( peptide-YY) and ghrelin secreted from the intestinal system and regulating glucose metabolism. GLP-1 (glu**gon-like peptide-1) is secreted from L cells stimulated with the food at the ending part of small intestines and in the colon. GLP-1 (glu**gon-like peptide-1) hormone increases glucose-dependent insu**n release, glucose tolerance and insu**n sensitivity of cells. In addition, it reduces glu**gon (increases glucose) release and food discharge from the stomach. Patient undergoing gastric bypass operation face a significant increase at GLP-1 level starting from the 2nd day of operation, indicating that the effect of gastric bypass surgery on diabetes is independent of weight loss.
No change is seen at GLP-1 level in gastric band operations. In dietary treatment, there is no increase at GLP-1 level with weight loss and even GLP-1 level tends to decrease, which paves the way for diabetes. Ghrelin hormone is specially released from the stomach. It increases the feeling of hunger, thereby increasing food intake. It decreases insu**n release and causes diabetes by suppressing adiponectin release, which increases the sensitivity against insu**n hormone.
Ghrelin hormone level increases when patients try to lose weight by following a diet program. Therefore, both the feeling of hunger increases and it may lead up to diabetes. Since the feeling of hunger increases, the diet becomes unsustainable after a certain point. The serious reduction is seen at the ghrelin level after gastric bypass and sleeve gastrectomy operations. In gastric band procedure, ghrelin level and its response do not change. PYY (peptide YY) hormone is secreted from L cells of the intestine with GLP-1. PYY hormone reduces the feeling of hunger and restricts food intake; moreover, it recovers insu**n resistance with a direct effect. PYY hormone increases after gastric bypass and sleeve gastrectomy operations.