I used to think that our body know better. But I realise it doesn't do what is better but rather what it is used to do.
I felt I had to eat sweets frequently, drink coca-coca everyday and 3 meals a day etc. My body felt terrible when I didn't. I stopped listed to what my body wanted and consciously stop those things. First week it was really painful. Second week I got used to. Third week I completely changed. Now I have to force myself do eat sweets, drink soda or having so many meals a day.
I still listen my body about drink water and not sure if I should really listen it when it comes to sleep.