You made a solid point, but I disagree to a certain extent. I think it's not so much about "access" that it is "excess." We eat way too much than what we need. Whatever carbs people back in the hunting days used to eat, If we ate that exact amount, we'd still be getting fat because most of us are at a job that involves sitting behind a desk. We don't use what we eat.
You have actually given me a nice idea and maybe in one of the next episodes of this series or later i'll explain the biochemistry of why eating too much carb makes us fat.