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McDonald's is now posting calorie counts on its drive-through and restaurant menus. That means no more ordering the Double Quarter Pounder with Cheese (750 calories) and letting yourself believe that's a light lunch.

The fast-food chain is making the move in advance of the Affordable Care Act, which requires restaurants with more than 20 locations to post calorie counts. But will the change alter anyone's eating habits?

The hope, of course, is that an educated consumer may be a less gluttonous one. In New York City, where calorie counts have been posted in fast-food restaurants since 2008, one study showed no change in consumers' habits based on their purchases, even from those who reported that they had noticed the calorie information.

Marion Nestle, professor of nutrition, food studies, and public health at New York University, told Yahoo! in an email, "Lots of people pay no attention to the labels. But studies that single out people who do pay attention show that it changes what they buy. Calorie labeling certainly changes my behavior. If I see that a breakfast muffin contains 600 calories, I'll either leave it there or share it with a friend."

The flip side is that restaurant chains may have an incentive to offer healthier options (fewer calorie-bomb muffins, perhaps) rather than post a menu item with an off-the-chart calorie count. "It can be embarrassing, or shocking, so they end up changing the way the product is made," Margo Wootan, director of nutrition at the Center for Science in the Public Interest, told the Associated Press.

Still, be prepared for some sticker shock. Test your calorie IQ with this quick quiz (answers at bottom).

1. The recommended average daily caloric intake for an adult is:
A. 30,000 calories
B. 10,500 calories
C. 2,000 calories

2. The actual average daily caloric intake for an adult is:
A. 2,000 calories
B. 3,000 calories
C. 2,700 calories

3. How many calories in a medium-sized apple?
A. 93
B. 30
C. 300

4. How many calories in a McDonald's Big Mac?
A. 1,500
B. 550
C. 150

5. How many calories in McDonald's small french fries?
A. 410
B. 70
C. 230

6. How many calories in a medium-sized plain bagel?
A. 289
B. 25
C. 400

7. How many calories in a Krispy Kreme Original Glazed doughnut?
A. 75
B. 190
C. 750

8. How many calories in a McDonald's Premium Caesar Salad With Crispy Chicken?
A. 350
B. 640
C. 220

9. How many calories in a McDonald's Cheeseburger Happy Meal? (Includes cheeseburger, kids' fries, apple slices.)
A. 250
B. 470
C. 520

10. How many calories in 1 ounce of raw almonds?
A. 164
B. 190
C. 55