Nutrition labels are based on a 2,000 calorie diet. So what exactly do 2,000 calories look like?

Check out this video by Buzzfeed to see:

Portions are hard--hard to guesstimate, hard to visualize, and hard to stick to. As Editor Scott Mowbray recently pointed out, it's easy to be off if you're not measuring, and too much leeway can lead to a nutritional disaster.

For some people 2,000 calories is too much. For others (Olympic athletes, marathoners, Big Bird), it's no where near enough. But, if you're an average woman over 25, it's just right. In fact, you should be consuming 2,000 calories or less according to guidelines developed by our nutrition experts. Men get to eat slightly more, 2,500-2,700 calories. But they're stuck doing the math. That's right men, break out your calculators, because nutrition labels aren't accurate for you. Don't get too excited. You can have a few more calories, but you're stuck with us on sodium and we're pretty even on fat and protein, too.

Check out our guide to proper portions and take the portion control challenge! Let us know how you do and what strategies you use to stay under 2,000 calories.

Bonus points: check out WiseGeek's photos of what 200 calories (a perfect size snack) look like!