How come digestive enzymes are reduced after gastric bypass surgery?

Loss of physiology: Food normally is mixed with acid and mechanically broken down in the upper stomach. Small amounts are released through the antrum of the stomach, which goes through the duodenum and proximal jejunum. Various substances stimulate secretion of gut hormones and enzymes. In gastric bypass operations, the antrum, duodenum and proximal jejunum are bypassed and reduce levels of these hormones.