I’ve known dedicated vegetarians who are quite capable of making delicious meals while avoiding animal products entirely, but even they admit that it is very hard work and that getting the correct proteins, amino acids, etc. into their diet is a challenge in the absence of meat.
I’ve benefitted from greatly reducing carbs and favoring animal fat over vegetable oils. Everything in moderation. Anyone who absolutely insists that this or that diet is the only correct way to go for everybody is trying to sell something.
Are you trying to sell something?
There is NO place on Earth where people could live JUST on locally grown fruits and veggies.
Meanwhile, the early Eskimos demonstrated that you CAN survive just fine on a meat/fish diet.
Humans evolved as omnivores. We need a mix of fruits, veggies, and meat in order to have a balanced, healthy diet. With my wife's experiences on her paleo diet, we seem to do better when we reduce the amount of grain we eat. Eating processed grains is something we've adopted relatively recently, and the main advantage of grains were that they could be stored for long periods (a very useful trait in regions which have cold winters).
That cliché doesn't hold up if you actually think about it for more than half a second.