I think this one has to do with "late dumping syndrome"-- basically, starchy foods cause hyperglycemia --> release of insulin --> catecholamine surge --> diarrhea, etc.
I had put "starches" b/c pts that undergo bariatric surgery are only supposed to eat complex carbs (fruits/vegetables) and avoid simple carbs (i.e. breakfast cereal/baked goods)
Thought this would be something regarding "bariatric surgery," but nope, just "no starchy foods, because you're pre-diabetic."
Because of the starchy nature of bread, rice, and pasta, after your surgery, they can form a paste in your throat that is hard to swallow without liquid. In some cases, they can block the stoma, the hole to the pouch that is your new stomach. You don’t have to completely reject these high-starch foods, but it’s best to avoid them in the beginning. When you do eat them, try to have very small portions and make sure that you only eat small bites of each.
I think it has to do with the surgery. Getting a gastric bypass or bariatric surgery means you no longer allowing contents to pass through the duodenum. So that would mean if you had a starchy meal you would not be able to release the appropriate enzymes from the pancreas to allow for digestion.
Please correct me if I'm wrong!