Some people's stomachs / digestive track may just not be compatible with that amount of meat as well.

That said, changing your diet this drastically will have results similar to the application of a new pharmaceutical drug. 99% of people could do it and be fine, but that 1% could have some weird things happen (e.g. the seasonal allergy story or some unusual digestive infection / issue). It's bound to happen just because everyone is a bit different in their genetic make-up. The same can be said for pharma drugs where 1 random person will have crazy weird side effects, which you hear rattled off at the end of drug commercials.

Great post and interest topic choice, @flountown!