That humans are apex predators, and we have been so for upwards of 2.5 million years. Following from this, I believe that most chronic illnesses that we have today (e.g. obesity, diabetes, mental illnesses, cardiovascular diseases, arthritis, PCOS, etc.) are caused by us straying from eating diets with lots of fatty meat.

According to people following the carnivore diet, they’re wrong.

Because:

• Ruminants like cows repair our depleating topsoil via regenerative farming (our current approach of using petroleum-based fertilisers is not sustainable)
• A single cow’s life can feed a human for 1 to 2 years, compared to the many incidentally killed animals (insects, rodents, frogs, birds, etc.) during the growing and harvesting of crops, plus the destruction of entire ecosystems to create the mono-crop farms in the first place
• Humans need to eat lots of fat to be physically and mentally healthy, and beef provides lots of fat (the low-fat high-carbohydrate diets recommended by various agencies — starting with the US’s department of agriculture in the late '70s via the food pyramid — are making us sick, with once-rare diseases such as cardiovascular disease, diabetes, depression, and dementia now commonplace)