Why Do People Eat?

People eat to provide their body with enough nutrients to help body operate successfully.
Just like a machine e.g., Car needs fuel(e.g., Petrol) to keep on running. If we don't fill Car's tank with fuel, then a time would come it would consume all the fuel and stop.
Same applies to human, the food they eat, provides them with nutrients that nourishes all parts of human body and in turn their body keeps on working without any problem. Remember that more healthy the food is, more healthy and efficient working the body would be. If humans eat food but that food isn't hygenic, then that would work as slow poison and effect normal working of body.