You are right there are many different types. I will highlight the 3 most common procedures for you to consider:
In gastric bypass, the surgeon creates a small pouch at the top of the stomach. The pouch is the only part of the stomach that receives food. This greatly limits the amount that you can comfortably eat and drink at one time.
In a sleeve gastrectomy, part of the stomach is separated and removed from the body. The remaining section of the stomach is formed into a tube-like structure. This smaller stomach cannot hold as much food. It also produces less of the appetite-regulating hormone ghrelin, which may lessen your desire to eat. However, sleeve gastrectomy does not affect the absorption of calories and nutrients in the intestines.
In the adjustable laparoscopic gastric banding procedure, a band containing an inflatable balloon is placed around the upper part of the stomach and fixed in place. This creates a small stomach pouch above the band with a very narrow opening to the rest of the stomach. A port is then placed under the skin of the abdomen. A tube connects the port to the band. By injecting or removing fluid through the port, the balloon can be inflated or deflated to adjust the size of the band. Gastric banding restricts the amount of food that your stomach can hold, so you feel full sooner, but it doesn't reduce the absorption of calories and nutrients.
In general, gastric bypass patients will lose around 70 percent of their excess weight, sleeve gastrectomy patients will lose around 60 percent, and gastric banding patients will lose around 50 percent.
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