How long does it take for a vegetarian to lose tolerance for meat?

It depends on how long they were vegetarian. If a person has been vegetarian for only a few months, they should easily be able to begin eating meat again.

If a person has been vegan or vegetarian for at least a year, they should begin to incorporate meat into their diet slowly. This can begin with incorporating dairy products and eggs, then mild fishes, followed by turkey and chicken and then pork and red meat. Suddenly eating meat after a long span of time meat-free can cause stomach and intestinal distress.