the body seeks to maintain a stasis. yours has adapted to the chemicals you have eaten and, just like if you were doing heroin for a while and then took it away, you are having withdrawal. those chemicals stored in the fat and other tissue of your body are not rendered harmless, its just that their effect is greatly diminished by insulating them in lipids.
so you have two things going on. one is the poisoning from the released toxins and the other is the withdrawal from the removal of those chemicals. the body wants to go back to what it is used to. it takes about three weeks to convince the body that things have changed.