Welcome to the board, Corrine.
The explanation for the surgery that removes part of the stomach is in the following post.
http://www.renewedreflections.com/fo...html#post28256
The illustration of the procedure is in the thread Kenayr has linked.
Now, to clarify the confusion.
1) The stomach does produce SOME enzymes necessary for digestion, but NOT the most necessary ones. The major ingredient of stomach juice is acids to break down the outer surface of the food, so the other enzymes can get to work faster.
2) The specific enzymes needed for breakdown and absorbtion of protein and fat are produced by the pancreas and the liver, and excreted through the bile duct into the duodenum, the portion of the small intestines closest to the stomach, so, as long as the liver, the pancreas, their respective ducts (the pancreatic duct opens into the bile duct) and the duodenum are intact, you will be fine.
3) is the reason for the Y bypass--to ensure that the enzymes from the PANCREAS and the LIVER, not the stomach, gets mixed with the food that comes through the pouch.
4) While DS/BPD are usually performed with revision cases, in Europe, that is the most popular type of weight loss surgery, not the Roux-en-Y. So, DS/BPD isn't always for revision, and more surgoens are doing them, and the sleeve gastrectomy without the switch, as the original surgery for weight loss.
5) The number of sleeve gastrectomy is increasing rapidly in the US, and there is an ongoing study sponsored by NIH (in other words, financed by grants from NIH) nationwide (US) to assess and compare the results of this surgery with others.
I hope this helps you understand and get a clearer picture, so you can decide what is best for you.
((((((HUGS)))))) May your journey go well.