Let me point out something about "health food" as described by UltraViolet in the post above:
Sure, depending on the area in the US - organic foods may cost more. Sometimes organic foods are not readily available for that matter.
But in the VAST MAJORITY of the US, fresh fruit, fresh veggies, natural cereals, etc. ARE available. They may not be "organic," but the produce aisles of nearly every grocery store in the US are full to bursting. You can buy oatmeal, rice, dried beans, cornmeal, unbleached flour, milk, real cheese, and inexpensive cuts of meat just about everywhere also.
In the US, a person doesn't have to restrict themselves to expensive, specialty items in order to eat more healthily. However, the sad truth is that most Americans prefer an unhealthy diet and lifestyle. Last time I checked, oatmeal, store brand milk, eggs, a bag of apples, beans, a whole chicken, fresh brocolli, etc were not prohibitively expensive. Chips, sodas, Cheeze Whiz, Capn Crunch with Crunch Berries, lunch meats, Hot Pockets, frozen french fries, etc are generally more expensive than foods that may require 10 extra minutes of preparation (and which are healthier).
So - it's not that Americans in general have such limited food choices - my gosh, that's a laugh, just walk down the aisles of nearly every grocery store in the US. It's not that we CAN'T eat healthier because it's more expensive.
My husband and I changed our diet about a year ago, and cut out processed foods, junk food, etc. We no longer buy canned veggies, sodas, chips, frozen foods, etc. We now stick to whole grains, fresh fruits and veggies, red meat only once or twice a week, etc. We don't shop at specialty stores - in our small town in East Texas, both Wal Mart and Brookshires Grocery carry all the basic foods we've needed in order to upgrade our diet. We rarely eat out in the evenings - we cook at home - FROM SCRATCH (gasp!!!!).
Our grocery bill has dropped significantly -- and we've both lost about twenty pounds. Our cholesterol levels are much improved and my husband doesn't have heartburn anymore. We feel great and are spending less money.
We have a lot of options here - it's just a matter of making fewer excuses and better lifestyle choices.
Oh - and walking is free exercize. But you gotta get off your butt and actually do it.