Aside from the fact that there are not enough pigs and cows on the Earth to feed every person in such a high-fat way, this kind of meaty diet is dangerous for both human health and our planet's future.

That doesn't stop people from trying.

"Eating a keto diet that's especially high in red meat will be undermining the sustainability of the climate," Harvard nutrition professor Dr. Walter Willett told Business Insider. "It's bad for the person eating it, but also really bad for our children and our grandchildren, so that's something I think we should totally, strongly advise against. It's — in fact — irresponsible."

Keto diets run on all different kinds of fat
Trendy keto diets are designed to make people run on fat, strictly limiting a person's carbohydrates,so that the body switches into a fat-burning state called "ketosis." In practice, this usually means no sugar, no wheat, no beans, and very little alcohol. Sometimes, it also means a lot of red meat.