"Limit your snacks to unprocessed plant foods."
Americans have added an average of 500 calories to their daily diet since 1980, which just so happens to be when the obesity epidemic began. The bulk of these excess calories have come in the form of salt, fat, and sugar laden processed snack foods. If you are going to snack, limit your choices to fruits, veggies and nuts.
All the tips given for the 28 Days of Real Food Challenge were compiled from "Food Rules", by Michael Pollan.