Here, we investigated the following hypotheses: (1) HSPs are secreted in the proximal small bowel in response to diets rich in fat; they negatively regulate insulin sensitivity and induce other pathophysiologic mechanisms of diabetes and NAFLD; (2) such proteins are reduced by DJB; (3) antibody neutralizing the activity of these proteins can recapitulate the beneficial metabolic effects of GI surgery. Here, INS is linked to diabetes mellitus.