When I went to UK before transferring, I often walked the mile from my house here in Lexington to campus........got honked at quite a bit too so it boosted my ego
If i had a bike(thanks mom for selling it without permission and then not telling me) I wouldve rode that quite a bit too.
I do think that weather plays a big role, as well as town/city layouts.
Our genetic make ups today are not different than those of humans in the days of "cave men" so to speak, nor is our metabolism. Compare the diets and physical activities of then and now. They were much more active, being walking everywhere and having to chase/stalk and then preparing to eat their dinner. Today we have processed foods that are ready to eat loaded with excess salt/sodium, trans fats, carbs etc by way of fast food, tv dinners etc. Our lifestyles today are also much more sedentary---we drive, we sit at home, we sit at work, we take elevators for one or two floors instead of taking the stairs, we drive around and around hunting the closest parking space to the entrance(which also wastes gas and time) instead of parking farther out and walking to the entrance........etc etc.
In short, I think while society dictates the necessity/desire to be skinny and to exercise, I think modern technology as well as society also encourages laziness and unhealthy eating.
Not to get too far off topic but next time when you are watching your favorite tv show....count how many food/snack commercials you see in that 30 minute or 1 hour time slot.