You know bears eat soil in in the winter to block their bums to store food? Well, if you don't go to the toilet often enough then the same will happen to you. Your body can't remove the fat if your body can't remove the food waste.
So, if your only a little bit chubby then a couple of days and you will look great though the sewage works manager will probably be a little bit confused?
Others will probably take a while longer. Don't hurt yourself.
A delicate subject though a little bit of humor.
Your eat more, your muscles will become stronger and your skin will look great too.
After a while fat rots which will make you feel ill.
This advice is not on any forum I know of...