I understand that the sugar in fruit, when eaten in its natural form, is less fattening that its juice, because of the fiber. Am I losing this fiber when I pulverize the fruit for a smoothie in my blender?
Juice is a challenging drink that is often misunderstood.
When you compare the number of calories in a glass of apple juice vs. the calories in an apple, there is a dramatic difference. A 16 ounce bottle of apple juice contains 220 calories. A large apple, by contrast, comes in at only 116 calories. The problem is that most of the juices you purchase in the store have had all the good stuff removed.
A lot of that good stuff is the fiber. We know that when foods that contain higher amounts of simple sugars are consumed with fiber there is a blunting of the rise in blood sugars and insulin release. This, along with other factors, appears to lead to greater satisfaction when we consume foods that are higher in fiber.
The 220 calorie bottle of juice contains no fiber, while the large apple has 5 grams of fiber. This is why I don't generally recommend having juice. It offers quick calories but not longer term satisfaction.
If you are going to make a smoothie using fresh fruit, however, it is almost like eating the fresh fruit. Your smoothie made with fresh, whole fruit will contain the fructose sugar but also the fiber that is so good for you. There may be some differences in how the smoothie satisfies as opposed to actually biting into and chewing an apple, but those variations may be subtle.
Making your smoothie with plain low fat yogurt may help offset the loss of satiety that from drinking your apple vs. eating it. The added protein, coupled with the quality carbohydrates and fiber in the smoothie, can be very satisfying and hold you throughout the morning until lunch.
I love when people eat fresh fruit. Snacking on fruit is great for you and making your fruit into smoothies can be good as well - as long as it is the whole fruit.
Thanks for writing,
Timothy S. Harlan, M.D.