Just as well there are probably people who can not eat a meat diet and be healthy, for example if they are allergic to eggs, milk or some meat variants. In fact

Just as well there are probably people who can not eat a meat diet and be healthy, for example if they are allergic to eggs, milk or some meat variants. In fact the percentage of people who can't deal with milk is very high. If you go into a normal supermarket, it is actually very difficult to find any foods that don't have milk in it (Lactose being used for lots of dirty tricks). The symptoms she describes (bloated belly, increased heart rate after eating) sound to me more as if there were some other problems - maybe she couldn't deal with some parts of the food very well. I've just read a good book about those problems (it is not allergies, I don't know the proper translation), and for example up to 17% of humans in the western world have problems digesting fructose. So naturally stuffing themselves with vegetables might cause problems. In that book it is also explained that those problems can often be cured in a matter of weeks. Few doctors are knowledgeable about those, though.