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 twice that at 16 or 24 ounces. Some smoothies are also overloaded with other foods, like granola and more fresh fruit. But in reality, you don't need these add-ins. Measure out 8 ounces and freeze the extra for later. When you order out, order the kid's size it's usually closer to 10 ounces. Or, ask for two cups and divide it up so you aren't tempted to drink the whole thing in one go. You can always freeze or share your uneaten portion. Even low-calorie foods like fruits and vegetables add up. And many smoothies include ingredients like yogurt, whipped cream, sweeteners, sorbet, or even ice cream that increase the calories. Bottled and made-to-order smoothies can easily pack in 300 to 600 calories in 16 ounces. "Don't assume that one package or one bottle is one serving," says Groppo. "Look at the nutrition label to see how many servings are in it." Keep an eye out for smoothies with added nut or seed butter, coconut oil, or avocado, as these all add significant amounts of calories. If you grab a smoothie for a snack, don't forget to include it in your total calories for the day.