What you are describing with meat is what happens not long after eating too much. In fact, other than lactose intolerance, it is rare to have issues that are not due to eating too much. Sure, there is a disease you can get from ticks, that can make you unable to process a protein, found in all animal products. Friend of mine has it. However, rare. Far more people have type one diabetes precluding them from eating a bunch of vegan friendly food.

That vast majority of people have bad reactions to hurting others though.