Can you have severe hypoglycemia after rout n ry?

Yes. Roux-en-y surgery (gastric bypass) causes side effects in about 40% of patients. Many of these are minor or transient but some can persist. Hypoglycemia is one of the more serious ones, and is incapacitating and dangerous. It is caused by high Insulin and glp-1 secretion for prolonged periods after meals. Difficult to treat other than eating small low glycemic index meals to reduce Insulin peaks.