LAB 2 – Carbohydrates
Background: Carbohydrates are one of the three macronutrients, which provide energy (calories). They can be classified as simple or complex. Simple carbohydrates contain either one molecule (monosaccharide) or two molecules (disaccharide).
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Monosaccharide + Monosaccharide |
Disaccharide |
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Glucose + Fructose |
Sucrose |
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Glucose + Galactose |
Lactose |
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Glucose + Glucose |
Maltose |
Complex carbohydrates contain long chains of glucose molecules called polysaccharides. These include starch, glycogen and most fibers. Fiber is either soluble or insoluble. Most fiber is composed of carbohydrates that people are not able to digest; therefore it adds no calories to the diet. All fiber provides health benefits that include delay in the onset of hunger, blood sugar regulation, prevention of constipation, reduction of blood cholesterol and promotes beneficial bacteria in the large intestine. Dietary Guidelines for Americans (DGA) recommends 14 grams of dietary fiber per 1,000 calories consumed.
It is recommended that half of the grains you consume should be from whole grains. Whole grains contain the entire seed (bran, germ and endosperm) and are good sources of fiber, vitamins and minerals.
Most breakfast cereals contain refined grains that have been milled to remove the bran and germ, leaving the endosperm that is composed of starch. This results in a low fiber grain with few vitamins and minerals. To offset this loss, the refined grains are enriched with vitamins that are added back to replace those lost during the milling process.
It is recommended that added sugar in a food should be less than 50% of the total carbohydrate of that food. Many convenience foods will contain large amounts of sugar, such as in cakes, pies, cookies, candy, etc.
Nutritive vs. Non-Nutritive Sweeteners
Nutritive sweeteners provide calories (energy), such as sucrose (table sugar), fructose, honey and brown sugar. Other nutritive sweeteners include sugar alcohols, such as mannitol, sorbitol, isomalt and xylitol. These sweeteners are absorbed slowly, therefore minimizing the impact on your blood sugar.
Other products have been produced to replace nutritive sweeteners. Non-nutritive sweeteners provide little or no calories. The most common non-nutritive sweeteners are aspartame, saccharine, sucralose and acesulfame-K.
Using Nutrition Facts to Build a Healthy Diet
- <5 grams of fat per serving and no trans fats; limit intake of fat, saturated fat, and cholesterol
- 3 or more grams of fiber per serving; goal is 25-30 grams per day
- Total grams of sugar should be less than ½ (<50%) of total grams of carbohydrate
- Limit sodium to <2400 mg per day; choose options with <150 mg per serving
- Increase intake of foods containing Vitamins A & C, Calcium and Iron
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