Smoothies may seem like the perfect drink for kids. It's real fruit that tastes more like a milkshake. But before you start divvying out the straws, beware: Some smoothies can be real gut-busters, topping out at more than 700 milligrams of sodium. There's nothing healthful about that. Although some smoothies are made from skim milk or yogurt and fruit, you'll want to keep these ingredients off the menu: sweetened syrups, ice cream, peanut butter and chocolate. Otherwise, what your kids are sipping may just put a double cheeseburger to shame.