Not to resurrect a thread but I would like to say this: Japan doesn't eat hot pockets or fried twinkies. My point was American food (and food from other developed nations) has more preservatives and fat in general. The food I get at a Japanese 'fast food' restaurant is handmade noodles and onion, with a little bit of beef.
Either way, watching how much you eat in general is a good idea. If you have a desk job, you don't need 2000 calories a day. That was my point.