Most of the natural sweeteners in your diet are sugars, or simple carbohydrates, and they're actually composed of several "building block" sugars called monosaccharides. Each sugar is made up of a unique combination of monosaccharides, from whence come that sugar's particular sweetness, color and texture. Table sugar (or sucrose) consists of equal parts fructose, the sweetest monosaccharide, and glucose. Glucose paired with another monosaccharide, galactose, form lactose, the sugar found in milk.
All sugars supply 4 calories of energy per gram, and -- this is important -- no nutrients. Just pure caloric energy.
A related group of substances, sugar alcohols, are chemically similar, but with a distictive difference that renders them less sweet and lower in calories. Although they do occur naturally, especially in fruits, most alcohols in foods are manufactured from sugars and added by processors.
Why add sugars and sugar alcohols in the first place? Because, in the home or the industrial kitchen, they work magic in foods. They add sweetness, of course, but also texture, moisture and color. They enhance and balance other flavors. Sugar is a preservative, used to cure ham and can figs. Without sugar our modern diet wouldn't just be unpalatable, it would be impossible.
Unfortunately, we've let sugar hijack that diet and drive us toward nutritional ruin. Americans, for example, down the equivalent of 20-odd teaspoons of added sugar every day -- 12 teaspoons in one can of soda alone. That's way over the American Heart Association's recommended daily limit of 6 to 9 teaspoons. Besides its well-known role in tooth decay, sugar has become a leading contributor to obesity. Sugary foods can crowd out more nutritious choices. That can of soda has roughly the same number of calories as a glass of milk, but only one of the two contains vitamins and minerals.(Guess which one.) And for people with diabetes, a sugar rush in the bloodstream can overwhelm the body's ability to produce enough insulin to metabolize it.
But there's a larger impact. Sugarcane farming is a chemical- and water-intensive process, and is centered in some of the world's most ecologically sensitive areas. It has drained and poisoned wetlands in the Forida Everglades and the Great Barrier Reef and shrunken life-giving rivers in West Africa and Southeast Asia.
After taking a minute to chew on that, delve into the next topic in our discussion: artificial sweeteners -- the promises and the pitfalls.