I can’t comment on the northeast, but I can say I was one of the more fit guys around town when I lived in the south simply because I did the bare minimum of exercise. The food is incredible and the weather encourages you to sit inside and hide from the heat.
Then I moved to Denver, where I am now the fat guy in the neighborhood. I quickly lost 20 lbs doing nothing besides not living near southern food and going to the mountains on the weekends.
To be fair, right around 50% of us are vehemently opposed to this sort of thing. Far from all America