CHEMISTRY HOMEWORK HELP: Hess's Law?

When eaten, oil molecules, such as those in olive oil, go through hundreds of reactions in the human body. Eventually, though, the final result is that the oil molecules and oxygen (breathed from the air) are metabolized into carbon dioxide and water molecules. If you add up the enthalpies of all the reactions involved in this process, would the overall result be exothermic or endothermic?

My teacher told me the answer is simple all I have to do is read Hess's law. I've reread Hess's law 3 times and I just can't grasp it how to answer this.