Where did we get the idea that eating meat might kill us? Probably from the very powerful lobby which is Veganism.
Now, of course there is a huge debate about how best to feed the world, and it has been decided by the powers that be that this is with grains. The Vegan lobby has told us that it is much more sustainable to feed the growing human population on grain, one of, if not THE most unnatural foods on the planet. Of course they can claim the moral high ground by saying it is unkind to keep animals in order to kill them for food. Many meat eaters are feeling guilty about their carnivorous habits as a consequence.
Taking the ethical arguments out of the equation, however, vegans will also tell us that their way of eating (despite the micronutrient deficiencies in it) is HEALTHIER than that of the more conventional omnivorous diet. This is a whole different ballgame. It is fine if these people are so against killing animals for food that they choose to compromise their own health for their principles, but to convince us that eating a wide variety of foods, including meat, is harmful? Who are they kidding?
The fact is that the vegans believe that our ancestral past (as "cavemen") was much more as gatherers than hunters. The paleo diet advocates would have us believe that the hunting part (and then eating all parts of the animal including the nutritious offal) is more of a realistic model of an ancestral diet. However, the fact is that most vegans are not nibbling on nuts, seeds and berries, but eating a huge part of their diet as grains. The meat-eating paleo and low-carbers are not. Eating meat, including all the healthy fats on the animal and the organ meat, is surely better for us than eating wheat, which is one of the most processed foods known to man?
Meat contains a good deal of nutrients especially fat-soluble minerals and vitamins which the vegetarian has to supplement - even to the extent of having injections of Vitamin B12. Meat has been part of our diet for centuries and whatever the ethical arguments about buying supermarket cuts wrapped in cellophane and not hunting it for ourselves, it is a healthy part of our diet.
One vegan / vegetarian argument is that we are omnivorous - that is we can live on a variety of foodstuffs, including fruits, nuts, legumes, vegetables - and meats. However they somehow manage to twist this argument to say that if we have evolved to eat this variety - to eat, effectively, almost anything - then this gives us a choice of what we eat, and that should exclude meat. If we have evolved to be omnivorous - that is a combination of carnivore and herbivore - then that means we should avail ourselves of all of the bounty the earth has to offer - and that includes meat.