I think it has more to with availability of bad food; very abundant in our modern world?
It’s not the veggies, it’s not the fruit, it’s not the meat (four legged livestock, fish, poultry, eggs), it’s not the fat!
It’s the 1. refined-carbohydrates or non-refined-carbohydrates (eating to much of it?) and 2. refined sugars and even natural sugars (eating to much of it?) or anything that has been processed with something or not used when it’s fresh?
If we really look at a vegan, ketogenic or carnivore diet, low-fat or high fat or any dietary methods, what do all centurians who experience longevity not eat?
It does not matter (it really does not) what method is chosen, the body will adapt to it, eliminating those two enigmas above are what extend the life-span and prevent most disease caused by those two factors, perhaps autophagy makes it (longevity) even better?
Blaming natural organic veggies and fruits or natural organic starches from plants for our WOE’s is like saying “I am going to cut off my arms and legs” and most people will do exactly that because they are not thinking? That said, your going to get the same nutritional density from plants, vegetation and forage by eating four legged animals, poultry, eggs or marine-life from eating their flesh and where is it coming from? Plants, forage, plankton, alga, kelp and vegetation; so whether it goes through you or them, it really does not matter?
Not getting enough vitamins, minerals and rare trace elements from natural organic sources within the amount of substance we put (nutritional density) in our body constantly…then add highly refined and processed foods especially sugars[1] and grains not used within 48 hours[1] of being milled to that type of dietary deprivation and what do you get? FAT (eventually) around the internal organs, inside the internal organs and skeletal muscle tissue as well as calcified organ tissue and calcified arteries etc…
Footnotes:
[1] …imagine the dysbiosis of the gut flora biome that is being created (fermenting and culturing or out-of-place-bacteria?) in the gut by that alone along with high fructose corn syrup (HFCS) and causing all kinds of autoimmunity, fatty liver (visceral fat) and obesity problems etc?