God. This reminds me of when I was anorexic, which for obvious reasons did NOT turn out well, as I lost 20 pounds and my blood pressure was something like 50/30...
In any case, eating healthy and exercising is the proper way to lost weight and detox your body. Not by starving it of the nutrients it needs to keep on running. Because like others before me have said, your body will start consuming its own tissue and muscles to give it energy. Not good at all. Been there, done that, and it's one of the worst things you can do to your body.