When you pick up a tempting food, scan the nutrition label, and think, "Wow, cool" -- because it's surprisingly lite, low-cal, or free of trans fat -- you expect those claims to be bona fide, right? Hah! Food packagers can be oh so sneaky. Here are four typical traps to watch out for:

1. When it comes to comfort food, does it have to be Kraft Macaroni & Cheese? Look twice. Like many boxed food mixes, the confusing label lists two sets of nutrition stats -- and the first one is for the dry mix only. Unless you plan on eating your mac-cheese mix straight from the box, the prepared version (made with margarine and 2% milk) adds an extra 15 grams of fat and 150 calories per serving to the first set of figures on the label.
2. Just downed a tall can (23.5 ounces) of AriZona Mucho Mango juice blend? Brace yourself. The sugar hit is 75 grams, not 25, as a glance at the label suggests. And the calorie hit is 360, not 120. That's 'cause one serving is only 8 ounces -- you're supposed to save the remaining two-thirds of the can for two more drinks!
3. Snacking on one of those smallish 3-ounce bags of multigrain SunChips? Smart, but note the itty-bitty serving size -- only one-third of the bag! Scarf down more, and you might as well be noshing on Oreos.
4. Sometimes, you really need a cookie, right? Happily, the nutrition label on your fave brand says 0 grams of fat and trans fat. That's good enough that you can deal with the sugar guilt tomorrow, right? Sorry, but 0 doesn't mean zero. It means "less than 0.5 grams per serving." Sure, that's not much -- unless a serving is, say, two Snackwell's Chocolate Mint Cookie Cakes, and by midnight you've finished the whole box. (Who, you?)

Shady labels like these give a whole new meaning to buyer's remorse. Wising up to nutrition tricks won't just keep you trim: Avoiding foods that list saturated and trans fats, simple sugars, or processed grains among their first five ingredients can make your RealAge 3.6 years younger. Sweet.