Sugar is the molecule that makes up carbohydrates, but there is more than one kind. There’s table sugar (sucrose) as well as the kind found in fruits and grains (fructose), the kind in milk (lactose), and the kind in malted barley (maltose). The sugars in milk and fruit tend to be absorbed more slowly than other sugars because they need to be converted into glucose by the liver first before your body can use them. That’s why these foods are relatively easy on your blood sugar.
Ironically, table sugar, which is half fructose and half glucose, is turned into blood sugar more slowly than some starches, like bread and potatoes. But that doesn’t make sugar — or its close cousin, high-fructose corn syrup — good for you. Why? These sweeteners aren’t as sweet as you think; it takes a lot of them to turn a food into the sweet treat you’ve grown accustomed to. That’s why one can of cola contains 40 grams of sugar. Fruit, by contrast, contains a little fructose plus plenty of water, fiber, and nutrients. A medium apple, for example, has 14 grams of fructose, but lots of terrific nutrients as well.