What nutrient do not undergo any chemical digetion in the stomach?

Fats do not undergo any significant chemical digestion in the stomach. While enzymes like gastric lipase are present, the primary digestion of fats occurs in the small intestine with the help of bile and pancreatic enzymes. The stomach mainly serves to mechanically break down food and mix it with gastric juices, while chemical digestion of carbohydrates and proteins begins there.