You may feel virtuous gulping down a hefty smoothie, but you're easily eating more than you realize. Smoothies can contain a pound or more of produce—significantly more than you would ever eat raw. All of that adds up to extra calories, carbohydrates, and sugar. A smoothie should be no more than eight to 10 ounces, according to Groppo. Most pre-made or made-to-order smoothies are nearly...