Weight loss after Sleeve Gastrectomy
The sleeve gastrectomy has overtaken the Roux-en- Y gastric bypass as the most common operation performed in the United States for weight loss. Approximately 50% of all weight loss procedures performed in 2014 were sleeve gastrectomies.
A sleeve gastrectomy is a surgical removal of 80% of the stomach, creating a tube or “sleeve”. In this procedure the small bowel is not re-routed or manipulated in any way. Despite this, the sleeve gastrectomy provides weight loss on par with the gastric bypass which has long been considered the gold standard for weight loss surgery.
Its easy to postulate that reduction of the volume capacity of the stomach accounts for the weight loss seen after this surgery. We are beginning to understand that this is only part of the reason that patients lose weight. In fact, the decrease in stomach volume may be less of a factor than thought. There are several other factors that lead to significant weight loss.
In fact, it has been demonstrated that a person’s basal metabolic rate increases prior to the actual ability to measure a reduction in weight. The stomach empties significantly faster after sleeve gastrectomy than compared to the “normal” stomach. This rate of emptying likely has a profound effect on several other factors that play a big role in weight loss. There are many factors that contribute to this remarkable phenomena.
Compounds like GLP-1 and PYY significantly increase and improve glucose metabolism, sensitivity to insulin and storage of excess calories. A decrease in appetite is the result of a diminished amount of the hormone, Grehlin. Additionally, changes in bile and nutrient flow has a profound impact on the bacteria of the GI tract favoring beneficial bacteria over their negative impact counterparts. All of these changes together lead to significant and durable weight loss. We are just beginning to understand these mechanisms. As our understanding of the mechanisms of weight loss improves so will the possibility of development of that “magic pill” to help us lose weight and keep it off.