Ever wonder who decides how many Gummy Bears = 1 serving? (18) Or that one cup of Wheaties = 1 serving? Well, nationwide food consumption surveys do, but also the NHLBI (National Heart, Lung, and Blood Institute). So if you're wondering why a serving of ice cream is usually only a Â½-cup (on their Web site the NHLBI says no more than the size of half a baseball), it's because that's what they've determined is the right amount to stay healthy. Meanwhile, we all know how many baseballs Baskin Robbins scoops into their hot fudge sundaes--enough to fill a small bathtub, right?

The NHLBI has studied portion explosion over the last 20 years and has done a lot of groundbreaking research. The good folks over at DivineCaroline.com used that research, re-purposed some NHLBI photos from a fun portion explosion quiz, and tell us that "in the 1970s, around 47 percent of Americans were overweight or obese; now 66 percent of us are. In addition, the number of just obese people has doubled, from 15 percent of our population to 30 percent."

Scary stuff, right?

This all starts to make a lot of sense when you look at the following images, culled from the NHLBI site and DivineCaroline.com. Clearly the majority of us are eating more than 18 Gummy Bears.

1. Two Slices of Pizza

You'd have to play golf (walking and carrying your clubs) for an hour to burn the extra 350 calories.

2. Bagel

You would have to rake leaves for 50 minutes to burn the extra 210 calories added over the last 20 years to the average bagel.

3. Movie Popcorn

You'd have to do water aerobics for 1 hour and 15 minutes to burn the extra 360 calories.

4. Cheeseburger

You'd have to lift weights for1 hour and 30 minutes to burn off the 257 calories.

5. Chicken Caesar Salad

Yes, even "healthy" food has exploded in size over the last 20 years. You'd have to walk your dog for 1 hour and 20 minutes to burn the 400 calories. (If you don't have a dog, you'd have to buy one first.)

6. Cup of Coffee

You'd have to walk 1 hour and 20 minutes to burn the extra 305 calories.

7. Soda

In the early '70s, 6.5 ouncers were popular. Today it's 20 ounces, or more (Super Big Gulp = 44 oz = 700 calories!) You'd have to work in the garden for 35 minutes to burn the extra 165 calories.

8. Turkey Sandwich

You'd need to ride a bike for 1 hour and 25 minutes to burn the extra 500 calories.

9. French Fries

You'd need to walk leisurely for1 hour and 10 minutes to burn the extra 400 calories.

10. Spaghetti and Meatballs

You'd need to houseclean for 2 hours and 35 minutes to burn off the extra 525 calories.