kokopuffs,
what you say about Europeans is basically right, even if stairs aren't probably the main reason why we walk more than you. The American Progress reached our Old Europe a long time ago, and most houses have now excellent elevators ;) . The fact is that in most european cities the services you need are often at walking distance and you "live" the town much more than in US. (In example, I go shopping everyday by feet, that means I walk with a couple of heavy bags, or pushing my daughter's scroller, about 1 hour a day...a good fitness exercise)
Another point is that usually Europeans (at least, the mediterraneans) are less addicted to junk food than Americans, and generally have more "dietetic" habits rather than a true dietary attitude.
A couple of examples?
The first time I've been in US I was shocked when found out that in most eating places you NEVER get the following items:
1) Plain mineral water;
2) Oil and vinegar to season salads;
3) Plain bread on your table;
4) Fresh fruit.
I'm sure you understand what I mean...
Pongi