Human beings are conditioned operantly by a punishment/reinforcement system.
When we eat vegetables we are punished by the intense amount of suffering we feel (hypoglycemia, headaches, intestinal pain). We learn, operantly, to avoid what causes us pain.
It's a natural, adaptive trait that allows for our survival.
If an ancestor ate something that made them ill, instinctively they would know to avoid that in the future.
I avoid vegetables because they make me ill. Period.
They can spout their B.S. statistics, conventional nutritional dogma all they want to. I will not eat things that cause me to suffer.