By Christina Fitzgerald, M.S., R.D., L.D.N., Contributing Editor
It’s easy to be confused by all the news about carbohydrates in food: good carbohydrates versus bad carbohydrates, complex carbohydrates versus simple carbohydrates, and—of course—fad diets that promote drastically cutting or eliminating carbohydrates altogether. In reality, carbohydrates come in many different forms and can be both healthy and unhealthy.
However, an arsenal of evidence shows consumers’ intake of sweet carbohydrates has drastically increased over the past several decades. Research has shown repeatedly that if we consume any one nutrient or total calories in excess of what the body needs, it can lead to poor weight management and chronic diseases. Today, 75% of total sugar consumed is in our commercial food supply. A 1998 USDA Economic Research Service report showed 45% of added sweeteners consumed go into beverages, 18% into cereal and baked goods, and 11% into confectionery goods (Agricultural Economic Report No. 772).
By definition, a carbohydrate is any group of organic compounds that includes sugars, starches, celluloses and gums, and also serves as a major energy source in the diet of animals. However, carbohydrates vary tremendously in sweetness, texture and rate of digestion.
Saccharide science
Not only does the sweetness differ greatly among these saccharides, but they are further differentiated by their chemical structure and divided into four categories: monosaccharides, disaccharides, oligosaccharides and polysaccharides. The sweetest carbohydrates include fructose, sucrose, glucose and lactose (galactose and glucose).
Glucose, or dextrose, (4 kcal per gram) is the most-abundant sugar found in nature, but it is seldom found in its monosaccharide form. It has approximately 75% the sweetness of sucrose. Glucose is typically found in nature as starch or cellulose, but also links with fructose to form sucrose. Fructose is the sweetest of all monosaccharides, about 1.4 times the sweetness of sucrose, providing 4 kcal per gram. It is known as natural fruit sugar; most fruits contain 1% to 7% fructose. The increase in sweetness as a fruit ripens is due to the separation of sucrose into fructose and glucose.
Sucrose, a dissacharide known more commonly as table sugar, cane sugar, beet sugar or even grape sugar―as well as being the main component in “natural” sugars, like turbinado—provides 4 kcal per gram. Sucrose occurs naturally in many foods, but is used abundantly in commercially processed foods.
