Katie Couric's Notebook: Snacking

Snack wraps. Snack cups. Snack packs. They're everywhere.

Taco Bell even pushes the concept of a "fourth meal" - just in case breakfast, lunch AND dinner didn't do the trick.

According to a new study, U.S. children eat nearly three snacks every day, consuming more than a quarter of their calories between meals...often in handfuls of candy, chips and cookies. And the greatest increase in snacking over the past three decades is among children between the ages of two to six.

The report, from the University of North Carolina, says American kids are "moving toward constant eating," a scary notion when more than 30 percent are already overweight or obese.

The First Lady is tackling the issue with her new Let's Move! program, and the USDA wants to ban junk food in school vending machines.

But eating habits are really shaped at home. We can start by avoiding anything with the word "snack" in its name...and by reminding our kids that the idea of three square meals doesn't include a fourth, packed with sugar, salt and fat.

That's a page from my notebook.

I'm Katie Couric, CBS News.