Go take a walk near any elementary/middle school in America and tell me you're shocked that we're seeing increased rates of heart disease among young people. The kids are totally screwed. They're abused by a society that feeds them garbage, keeps them sitting all day long, and makes it impossible for them to walk to a friend's house and play in the street.
By and large, the issue seems to be confined to the south and cornfed middle states who have an absolute explosion of childhood obesity. And it seems to have some association with some combination of factors of money, weather, and urbanism, but I don't know how/why.
it's not "better" imo, but i sure feel less sated after a plate of nyc fries vs central jersey fries
[1] https://www.mcdonalds.com/us/en-us/product/small-french-frie...
Of course what local restaurants use will vary wildly. Some will use high quality oil and some will use the cheapest food-grade oil they can find that has managed to get FDA/USDA approval (not sure which agency supervises that).