You'd think juice would be healthy—it's made from fruit, after all. Problem is, while fruit is rich in fiber, juice is not. So even if you opt for 100% fruit juice and avoid drinks with added sugar (like cranberry or grape cocktail), they're still high in the sweet stuff. For instance, a cup of grape juice contains 36 grams of sugar and a cup of apple has 31 grams—not far off from what you'll find in a can of lemon-lime soda, which racks up 44 grams.

Make over your drink: "I don't recommend juice ever, even 100% fruit juice," says Ilyse Schapiro, RD, author of Should I Scoop Out My Bagel? ($11; amazon.com). "You'll feel much more full from eating the fruit, which has fiber, versus drinking the juice," she says.