system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why is it that when an alcoholic stops drinking alcohol they become sick even though alcohol is incredibly bad for us, what is happening in our body that makes us sick for not having it?
gpt
Basically when you get used to a toxic substance being around, your body produces more of the chemicals needed to process it than it's normal for you to have. This is why people develop a tolerance. Some substances, such as alcohol, also alter the way systems in the body work, such as your digestion and nervous system. So when you stop having alcohol, your body is already not working right and it's flooded with chemicals that aren't normally supposed to be there, so it makes you sick. There's more to it than that, but basically it comes down to that. The body strives to be in balance, and after a certain amount of regulation, it becomes necessary for the alcohol to be there in order for things to stay balanced. Like when you have a really fat kid on the see-saw; if he suddenly jumps off  all the kids on the other side are going to come crashing down. That's what happens inside your body, the alcohol is the fat kid and all your body systems pile up to be able to balance it out, but they're pulling so hard the opposite direction that if the fat kid disappears, your body falls down in a heap.