The Scientist: Kristen Kirkpatrick, R.D., YouBeauty Nutrition Advisor.
Drinking that much sugar causes a big spike in your blood sugar and insulin levels, which then drop to below their original levels, bringing on the inevitable crash. Fiber—which is found in the peel and body of a fruit—takes a lot of time to digest, and sugar absorption slows along with it, giving your body enough time to process it properly. When the fiber is absent, you absorb the sugar very quickly, so it rushes into your bloodstream. What your body doesn’t use right away gets stored as fat.
You still get the vitamins and minerals, so it’s not a complete wash, but it is far worse for you than eating a piece of fruit. Grape and tomato juice, for example, have twice the sugar as the same amount of their chewable progenitors. Fruit juices generally have several times more sugar than vegetable juices.
It’s amazing (and kind of gross) how many calories you can gulp down without realizing it. A cup of blueberries, about 80 calories, could take five or 10 minutes to eat. But you could easily down a cup of blueberry juice, 130-160 calories, in 30 seconds.
A glass of juice a day won’t ruin your health. But if you’re craving the flavor of a ripe, crisp apple, go for the real McCoy (like a real McIntosh).
MORE ON SUGAR FROM YOUBEAUTY.COM:
The Downfall of Drinking Your Calories
Top 10 Sugar Foods (and Secret Sugar Foods)
The Less Sugar, Younger Skin Diet