How does dehydration synthesis and hydrolysis relate to harnessing energy from food?

Dehydration synthesis is a process where formation of  a water molecule takes place while joining two molecules. Hydrolysis refers to a chemical reaction where breakdown of water molecule takes place. Thus, both the processes are opposite to each other but are related to each other while harnessing energy from the food. During dehydration synthesis the food molecule is formed with extraction of water from the food while during hydrolysis digestion of food particle takes place and water molecule is used in the process.