Look at the facts. Humans go back a few million years. Our genes have evolved over all those years. Agriculture OTOH is only a few thousand years old. That is like less than 1% of time spent surviving WITHOUT agricultural products, mainly the grains (rice, wheat, corn etc).
Also keep in mind ancient humans did not live sedentary lifestyle. It was hunter-gatherer life, with miles of walking everyday.
I have concluded the best food for our bodies is what ancient humans ate...fruits, root vegetables, berries, green leafy vegetables, and occasional feasting on meat when they had a successful hunt. No added salt or sugar. Call it Paleo diet. And add a couple of miles of walking.
That won’t prevent bacteriological diseases, but it is likely to reduce degenerative diseases such as heart problems, diabetes, high blood pressure, muscle deterioration with resulting joint aches, etc.
however, it is likely that folks prior to agriculture and animal culture died at what we would now consider very young
However, reducing carbohydrates and eating butter pretty much ended indigestion and drooling at night
That’s what they said over at their site. It was very informative. Looks like you had already figured that out.