Explain the need for enzymes in digestion

Mechanical digestion breaks down large food particles into smaller ones, increasing the surface are to volume ratio. However, polymers present in food particles require a very long time to break down at body temperature - for this reason, the process requires a catalyst. The presence of digestive enzymes speed the rate of digestion up by over 1 million times, facilitating the breaking of chemical bonds and requiring a lower activation energy to initiate the reaction.