You don’t think people ate carbs 3 times a day in the past? The majority of humans for the majority of recorded history have eaten some kind of bread, rice, potatoes, porridge, or corn with the majority of their meals.
Also in the majority of recorded history being fat was a sign of wealth. I don't think the majority of humans had a surplus of carbs available to overeat them. It's not that carby foods are inherently bad, there's just something bad about the way they fit into modern society, for some people.
Modern wheat is a very modern invention. You have to be pretty gullible to believe that something that has only existed for 50 years has existed for millennia.
I know it's hard to believe in the US as today it even gets harder in Germany to find it.
The problem is eating shitty cheap mass produced food.
Same goes for "vegetable oil". Check out how it is made and you will probably respect olive oil more or some good ol butter.
Also it is possible to drink water. You don't need soda from dawn till dusk .