Remember when you were a kid and eating was as simple as "Open, chew, enjoy"? You didn't count the grams of fiber and fat in your PB&J. You munched when you were hungry, stopped when you were full and ran off to play with your Cabbage Patch Kids. But choosing a meal as a health-minded adult can be as complicated and joyless as a calculus final. Enough! Here are 20 commonsense rules that make eating right as easy as pie for you and your inner 8-year-old.