well, this is a bit of fun. wisegeek.com has this helpful page
with photos of food items weighing in at 200 calories a piece. scanning from the top down you can see where you'd get more bang for your buck.
imagine a world where processed food items were packaged in 200 calorie amounts, not oversized packages with a "suggested serving" size in small type on the side. i was reminded of this looking at some fancy vitamin water (the closest thing to lemonade i could find the other day) which i handily downed with my lunch; it suggested the bottle contained 2.5 servings but the only way to get the 100% vitamin c it contained was to drink the entire thing. confusing, deliberately deceptive, and frustrating.
but what if we had snack foods in 200 calorie sizes and the choice to eat was based on that knowledge? people standing at the vending machine looking inside going hmm, i could have 16 gummi bears or 8 hershey's kisses or half a snickers bar.
of course, we're americans. we're not going to let some fascist vending machines tell us we can't eat a bag of chips, a soda, and a candy bar with our lunch! 2000 calories, that's per meal, right