Provided herein are methods and shunt devices for treating diabetes and obesity. Methods and shunt devices promote stimulation of secretion of intestinal L-cells and other enteroendocrine cell types. Enteroendocrine secretion is stimulated directly or indirectly by shunting bile and/or pancreatic secretion to segments of the gut more distal than would normally occur. The shunt device may be a flexible catheter that is impervious to such secretions, with a proximal end draining the pancreatic/bile duct, and a distal end residing distally within the lumen of the small or large intestine. The shunt may be inserted with minimally invasive techniques, such as by endoscopy or laparoscopy.