Now Playing: Yogurt vs. Ice Cream: Which One Should You Eat?

Now Playing: Easy Ways to Lower Calories

Now Playing: Avoid These Calorie Catastrophes

Now Playing: The Sweet Truth About Chocolate

Now Playing: Start Your Day Off Right With a Glass of Juice

Now Playing: Military reacts to Trump's transgender military ban

Now Playing: 1 dead, 7 injured after incident at Ohio State Fair

Now Playing: Trump faces growing backlash over transgender military ban

Now Playing: Laura Linney opens up about motherhood: 'It's been fantastic'

Now Playing: Deals and steals: Back-to-school bargains

Now Playing: All the different ways you can fail a handshake

Now Playing: How to bling out your child's backpack this school year

Now Playing: US tourists in Mexico cautioned over 'tainted' alcohol

Now Playing: Angelina Jolie speaks out about her health battle and being a single mom

Now Playing: Ava DuVernay partners with Oprah Winfrey's production company

Now Playing: Hospital celebrates baby boom after Cubs' World Series win

Now Playing: Carbon monoxide poses risks for boaters

Now Playing: Experts warn parents about how Snapchat and other apps can hook teens

Now Playing: Video appears to show Justin Bieber in car incident

Now Playing: Great American eclipse sparks tourism boom