Through the activity of enzymes (amylase, brush border, digestive), dietary carbohydrates are digested into glucose, fructose, and galactose. Digestion is altered by factors such as: the availability of starch to enzyme action, presence of fat, which slows stomach emptying, non-absorbable oligosaccharides, and fibers. A diet rich in fruits and vegetables will slow the pace of glucose absorption in the body.
Glycemic Index
The glycemic index ranks carbohydrates based on their ability to raise blood glucose levels. The glycemic index uses of a scale of 0-100. Higher values are given to foods that cause the most rapid rise in blood glucose (Pure glucose = GI of 100). The glycemic index has been an important factor for diabetics that are trying to control their blood sugar spikes.
Glycemic Load
The glycemic load takes the glycemic index further by factoring in the type and amount of carbohydrate consumed. (Grapefruit: GL of 3, Potato Chips: GL of 30).
Regulation of Blood Lipids
A high carb diet leads to hypertriglyceridemia (high blood triglycerides). According to the NIH, "As compared with starches, sugars (particularly sucrose and fructose) tend to increase serum triacylglycerol concentrations by approximately 60%). Two hours after consuming a meal, blood glucose levels begin to drop. The body secretes counter-regulatory hormones that release free fatty acids from fat cells. The fatty acids are packaged into VLDLs and serum triglyceride levels are increased. On the other hand, a high fat diet does not translate directly into blood lipid changes. The body regulates macronutrient levels to provide adequate supplies of fuel to body tissues.
Fiber and Blood Lipids
Fiber is an important factor in weight loss and blood cholesterol control. Fiber prevents fat and cholesterol absorption by binding bile acids of fats and lipids and excreting them.
Mahan L, Escott-Stump, S. "Food, Nutrition, and Diet Therapy." Saunders. 2004.
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