Diet Information
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What Determines Glycemic Index Values of CarbsHow fast a particular carbohydrate food raises blood sugar is determined by several things. These include: the chemical nature of the carbohydrate, and the physical nature of the carbohydrate. Glycemic Index Affected by Chemical Nature of the CarbohydrateGlucose is the body's preferred source of energy and the body processes glucose very efficiently. (GI of glucose is 100.) But the body has a limited capacity for handling fructose, a common monosaccharide in fruits and honey, which is why fructose has a low GI of 23. Ordinary table sugar (sucrose), is a disaccharide made up of one molecule of glucose linked to one of fructose. Which helps explain why the GI of white sugar is 65, almost exactly midway between 23 and 100 in the intermediate range. Glycemic Index Affected by Physical Nature of the CarbohydrateThe precise physical nature of the carbohydrate in a particular food also affects the GI value of that food. For example, most breads are in the high range - not due to the chemical nature of wheat starch, but for two mechanical reasons. (1) The fine particle size of wheat flour gives digestive enzymes great surface area to attack. (2) The puffed-out structure of bread also increases the surface area of the food. The higher glycemic index value of bread is partly the result of this typical physical structure of bread. Glycemic Index Values of Other CarbsPasta has a low GI than bread - which incidentally can be lowered further by cooking it less (al dente). This is because al dente pasta resists the effect of digestive enzymes more than regular cooked pasta and so has a lower GI. Rice cakes have a very high GI because of their extremely puffed-up structure. In comparison, the glycemic index value of sugar is lower because 50 percent of it's molecules are fructose, which the body metabolises less efficiently than (say) glucose. For more information and comprehensive details on GI values for all popular carbohydrates, see Carbs and Glycemic Index Related Glycemic Index LinksGlycemic
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