I am thinking about trying that, too. But, you have to be fair that the sudden change from one extreme to the other just triggers a strong reaction from the body naturally. I assume the first two weeks of switching to only meat had also their side-effects? That being said, you might have just found something to avoid in the future.

If you want to do it properly, don't jump into a pizza right away. Start with something like plain potatoes or plain pasta.