system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 If humans can go weeks without eating, why do we eat 3 times a day?
gpt
So the trick is that you can go weeks without eating if absolutely necessary in an emergency. But your body needs energy from food to work. Everything from breathing to walking to thinking uses energy, and we get that energy from the food we eat.

If we eat more food then we need, the extra energy gets turned into fat and stored in our body in case of emergencies.

If we don't have enough energy, our body can break down stored fat and muscle and turn that into an emergency supply of energy. But it can only do that for so long, and doing that makes us tired and weak. 

Eating regularly is better for our bodies, because we get the energy we need to survive.