I didn't have the problems you have, but you may find answers in our archived posts here. This may sound stupid but I don't know what an endocrinologist knows about duodenal switch reactions. Malabsorption and malnutrition are indicators that you're doing something wrong as you consume food or can't consume food. Keep looking and keep asking questions. You know the difference between God and a doctor? God doesn't think he's a doctor. That's a joke I make when a medical professional doesn't seem to be making sense.
Also, you can search the archive here, but I've never even heard this term before and I've been here longer than anyone. I'd see another doctor. I'd also search my own beliefs and prejudices and see if it's possible I'm clouding the issue. Please don't think that's what I think of you. But I could believe that of me.
I'm so fascinated that you have duodenal switch. I want to know all about that. Only a handful of people here have ever mentioned having that.
I'm lucky to live in a big city where there are hundreds of places to use as resources. Whatever is going on with you, I hope you have enough resources to find your answers. I wish you the best.