The laparoscopic adjustable gastric band produces weight loss by restricting ones ability to eat. It places an adjustable band around the upper part of the stomach and the band is gradually inflated which produces increasing restriction on the outflow of this gastric pouch. As a result, different foods will not empty out of the pouch into the stomach very easily and may become stuck in the pouch causing an uncomfortable feeling and possibly causing emesis (vomiting).
Similarly, the roux-en-y gastric bypass creates a small gastric pouch, which is attached to a limb of intestine. This attachment is made in a variety of ways, but to be successful, it has to be somewhat restrictive so that food does not empty out of the stomach into the intestine too easily.
These artificial means of emptying which is not physiologic impede ones ability to eat various foods and the surgeon should discuss the fact that foods like red meats, pasta, salads, and to a lesser degree chicken and fish may be more difficult to eat and may in fact get stuck causing pain and possible vomiting. It is also stressed to these patients that one must be very deliberate when eating and to chew their food very well and to eat very slowly.
In the duodenal switch, the stomach is made into a narrow tube, which empties into the first part of the duodenum in the normal physiologic manner via the pyloric muscle. The function of this muscle it to monitor the contents of the stomach and regulate the emptying of the contents. If the food is not digested properly or is too concentrated, it is not allowed to empty and must undergo more digestion by the stomach. Again, the stomach still functions like a normal stomach and digestion does take place with the duodenal switch where in the laparoscopic adjustable gastric band pouch and the roux-en-y gastric pouch, digestion is significantly diminished and food will exit out of the pouch in much the same way it entered the pouch.
This allows people who have had the duodenal switch eat much more normally than those who have had the other two weight loss operations. In fact it is entirely normal for these people to be able to eat a small steak, chicken, salad, or pasta without difficulty where it is a rare person that can do this with the other two weight loss operations.
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