I have to admit that it's always kind of a shock for my wife and me when we arrive in the USA and are suddenly surrounded by so many obese people.
Especially at WDW with all those obese people scooting around on those
ECVs. We always ask ourselves: Do they use those contraptions because they are fat, or are they fat because they use those scooters
We've seen people leaving a shopping mall, boarding their car, driving it over to the next entrance, parking again, and entering the mall again.
We usually arrive at the parks very early and park our car i.e. in EPCOT very close to the entrance so it's just 400 or 500 yards, which we walk of course - Those obese people wait for the tram
We are also shocked by the package sizes of food in America: Potato-chips in bags that wouldn't fit into an average European compact car

Buckets of ice-cream instead of cups, etc.
We always see people in the parks munching those disgusting monstrous turkey legs while walking - in the morning

: Eating should be a conscious thing not to be done on the go. I've seen people during many cruises on Disney-ships carrying plates of desserts to their cabins - well after midnight!!
I also have to watch my weight: When I quit smoking more than seven years ago I gained about 40 pounds in two years, but with a strict workout I managed to shed half of it and turn the other half into muscle. The price I have to pay for it: I work out 5 to 6 times a week for about two hours each. I run about 30 miles a week, pump a lot of iron, play Badminton, do aerobics, in-line skating, etc. I eat lots of fruit, veggies, mainly poultry and fish. I avoid fast food. But nevertheless I eat chocolate or gummybears nearly every night. I don't drink alcohol - except when I'm on vacation.
And I walk as much as possible: In the office I try to walk over to people instead of using the phone, I use stairs instead of elevators, I always park my car far away from the grocery store's entrance - Mainly to prevent door-dings from kiddie-carriers

, but also to burn some extra calories.
When I do squats with a 200lbs+ barbell on my back I always ask myself 'What a strain it must be to carry that weight all day?' What kind of feeling must it be not to be able to run a mile? Not to see your feet? Having to pay all the extra expenses for XXXXXXL-clothes? Not to able to fit into an aircraft seat, etc?
But rest assured: It's not an exclusive American problem: Over here we are headed in the same direction:More and more obese kids, diabetes caused by malnutrition even in young people, etc.
A few people are fat due to a disease (i.e. glands, bad genes), but most fat and sick people are sick because of their weight: Diabetes, coronary problems, worn joints, etc. are very often caused by excessive weight.
My wife is a nurse on an orthopedic ward: 9 out of 10 hip replacements they have to do are on obese people. What for? If those people don't lose weight their new hip will have to be replaced very soon again. And who has to pay for it? Society!!
I guess meanwhile there is more damage done to the society by obesity than by smoking - But I've never seen a warning by the Surgeon General on a cup of Ben & Jerry's

Don't get me wrong: IMHO the battle against smoking is a just cause, but the same is necessary to fight obesity!!