Good nutrition starts with smart choices in the supermarket. But filling your cart with healthy foods isn't always easy, especially when the shelves are packed with thousands of products to choose from. "Markets perform a great public service, but keep in mind they are designed to get you to buy (and, therefore, eat) more food, not less," says Marion Nestle, PhD, MPH, a nutrition professor at New York University and author of What to Eat: An Aisle-by-Aisle Guide to Savvy Food Choices and Good Eating. But luckily, making healthy decisions is a cinch when you keep these guidelines in mind during grocery shopping.

Prepare a grocery list

Drawing up a grocery list is a great way to keep unhealthy foods out of the home. "Go prepared with a list of what you need to get," advises Lola O'Rourke, RD, a nutrition consultant and a spokeswoman for the American Dietetic Association (ADA). "That may sound obvious, but the next time you go into the store to buy something specific without bringing a list, see what you come out of the store with. Chances are you've got much more than what you went in to buy, and much of that may not be real, nutritious food."