A recent article in Scientific American stated that "hunting is what made us human". Basically our evolution from forest fruit-eating apes to hunters on the plains is what led us to become human. This suggests that for humans, eating meat is part of our natural diet.
The food guide relegates meat and dairy to an appendix. Emphasizing vegetable sources of protein leads to an unnatural diet.
It seems the never-ending propaganda of vegetarians and vegans is paying off. Yet these diets, especially veganism, are profoundly unnatural and cannot be good for our species.