Carbohydrates are contained in a vast and varied array of foods; everything from the most virtuous vegetable to the most decadent treat. All carbs contain sugars. These sugars, though, exist in several different forms and go by a variety of names, including sucrose (table sugar), lactose (in diary), and fructose (as found in fruit).
Despite that similarity no one who has ever craved a sugar doughnut has been satisfied by broccoli. The opposite might also be true, though it's difficult to find people who suffer from insatiable cravings for green vegetables.
It's easy to tell by taste which carbs are highest in sugars, and which yield their sugars most readily. It probably comes as no surprise that a milk chocolate bar gives up its sugars more freely than one made of dark chocolate; or a pineapple yields its sweetness faster than a grapefruit, or a slice of supermarket white bread produces blood sugar faster than a coarse-grained health food cracker. The more sugar there is, and the faster it's released, the more acutely we sense that sugar "rush" - the relief that courses through our bloodstream as we heed the call for carbs. Internally, though, our bodies treat all carbs in basically the same way - digestion is in large part the process by which our bodies extract the sugars from carbohydrates and turn them into fuel, which we either burn or store. Burning the fuel is good - that means we're active enough to make efficient use of the food we eat. Storage of a little fuel is all right, but anything more than that is not good. You know that excess stored fuel by another term: body fat.
The job of carbohydrate digestion starts in our mouths, when we chew the food into bits and our saliva begins the chemical process of separating each mouthful into its components. In our stomachs, the food is further shredded by the organ's muscular contractions and gastric acids. Our bodies want to get at the sugars contained in carbs, but this happens at varying speeds, depending on certain factors. Essentially, the less encumbered these sugars are by other substances, the faster they enter our bloodstream.
Carb Competitors
Which substances get in our bodies way? Fiber is the major factor that slows the absorption of sugar. That's the reason the highly processed oatmeal was worse, diet-wise, than the steel cut variety - the latter had all the fiber still intact, and so before the stomach could get to the sugars in the oatmeal, it had to separate them from the fiber. Once isolated, the fiber passes undigested through your system; its dietary importance comes from the ability to slow digestion down. It's an obstacle to digestion - a good one.
This was proven not long ago in a scientific study in which half the subjects were given the fiber known as psyllium (you probably know it better as Metamucil)15 minutes before lunch. The other half had lunch without the psyllium first. In the hours after the meal, the fiber group reported less hunger than the others. As the day wore on they ate less, too. The reason is simple: In their stomachs the psyllium mixed in with what they ate and drank and slowed down the digestion. Slower digestion of carbs, less insulin. Less insulin, less dramatic drop in blood sugar. Less of a sugar rise and fall now, less hunger later.
Fiber isn't the only thing that slows the digestion of carbohydrates. Fat, too, slows the speed at which your small intestine accessed the sugars you've eaten. That's why, in the study of overweight adolescents, the omelet breakfast created the least desire to eat more later. We have found other factors that slow the digestion of carbs and therefore benefit dieters. Acidic foods such as lemon and viegar slow the speed with which your stomach empties, therefore cutting back on the rise in blood sugar. You can dress salads or vegetables in both and enjoy the benefit. Even sourdough bread, while not high in fiber, is acidic, and will slow stomach emptying and thereby slow digestion.
This is an important lesson in eating properly and losing weight. This is why we call earbs containing fiber good, and why we also think of certain fats as good, too. Anything that slows the process by which you process the sugars in carbs is by definition, good. *~ Aunt Millie
* Taken from The South Beach Diet by Arthur Agatston, M.D. For more details, go to http://www.southbeachdiet.com
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