There is a question I encountered.
Why is fat harder to digest ? A) It has ester bonds. B) It is not easily soluble in water.
Which is the most appropriate answer?
I think that the main reason (but probably not the only one) is because fats are hydrophobic, while the environment of the digestive tract is aqueous. Most of the fats in the diet are triglyceride and in hydrophilic environment they form globules. Triglycerides must be hydrolysed to be absorbed by the duodenum and this work is done by pancreatic lipase, that is a water soluble enzyme and can only hydrolyse the esteric bonds at the surface of fat globules.
Therefore, during the digestion amphipathic molecules such as bile salts and phospholipids emulsify those droplets in smaller ones, increasing the surface area where lipases, together with colipase can digest.