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Chapter 2 Carbohydrates, Proteins, and Fats: The Energy Macronutrients of Balanced Meals Macronutrients Macronutrients provide kilocalories (kcal), a measure of energy Carbohydrate (CHO) and protein (PRO) = 4 kcal/g Fat = 9 kcal/g Alcohol (ETOH) = 7 kcal/g; alcohol is not considered macronutrient Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 2 Macronutrients (continued) Macronutrients are organic—they all contain carbon Fats contain more carbon, thus being higher in kilocalories Being organic, all three macronutrients are digestible—they can break down into component molecules All three macronutrients contain carbon, hydrogen, and oxygen Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 3 Foods Generally Contain a Combination of Macronutrients Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 4 Carbohydrates Made up of glucose molecules: C6H12O6 Three basic forms: Two sources: Sugar: monosaccharides and disaccharides Starch: polysaccharides Fiber: indigestible polysaccharide Plants (from photosynthesis) Milk Chief energy source for the body cells (sugar and/or starch) Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 5 Examples Sugar is noted with suffix “ose”: glucose = blood sugar; sucrose = table sugar; fructose = fruit sugar; lactose = milk sugar Glucose and fructose = monosaccharides Starch = polysaccharide; found in bread, peas, corn, pasta, and potatoes Fiber = indigestible polysaccharide found in plants; insoluble = skin and seeds and “crunchy” components; soluble = pulp and “gummy” components High-fiber foods have a relatively low glycemic index Glycemic load: a meal with a high content of CHO with sources that are high in glycemic index (quickly enter the bloodstream) Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 6 Food Label Guidelines 60% kcal as CHO (300 g per 2000 kcal) Total CHO = sum of sugar, starch, and fiber Fiber goal = 25 g per 2000 kcal Net CHO = total CHO minus fiber and 1/2 sugar alcohols *RDA for CHO: 130 g Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 7 Estimating CHO Content of Plant-Based Foods Assess 3 aspects of sensory experience of food: Level of sweetness Level of water Density • ½ cup fruit (sweet): 15 g CHO • ½ cup dry grains and dry (potato, legumes) or “sweet” • • • • vegetables (sweet corn, sweet peas): 15 g CHO 3 cups popcorn (low density): 15 g CHO ½ cup cooked or 1 cup raw low-CHO vegetables: 5 g CHO, (most low CHO vegetables sound odd to say, “sweet _____”) ½ cup flour (very dry): about 45 g CHO ½ cup sugar (very dry and very sweet): about 100 g CHO Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 8 Protein Attributes and Functions Protein is unique among nutrients because it contains nitrogen Because of its nitrogen content, protein is used as a building source for new body cells Protein is found in all body cells and constituents such as the immune system, hormones, and digestive enzymes Dietary intake digested into amino acids; the liver reassembles these into protein Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 9 Protein Sources Found in muscle (i.e., red and white meats and fish), eggs, nuts, legumes, milk, and milk products Limited amounts in grains and vegetables Only fats and sugars do not contain protein; fruit contains only trace amounts of protein and is generally considered to have none Essential amino acids (EAA)—eight required for adults, nine for children with need for histidine; certain quantity needed in the diet within a 24-hour period to make protein Complete protein source: a food containing all eight EAAs (animal products) High-biologic value diet: emphasizes foods with all EAAs Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 10 FYI Examples of EAA and Sources Methionine—primary source is animal protein; metabolized into taurine and homocysteine; contains sulfur; excess intake linked with bone loss, some chronic diseases (cardiac, Alzheimer’s, diabetes) Phenylalanine—found in aspartame (NutraSweet); all U.S. infants are tested for phenylketonuria (PKU) at birth; caution on labels aimed at individuals with PKU Tryptophan—found in high amounts in turkey and milk; precursor to the hormone serotonin (that promotes a “good feeling” and helps induce sleep) Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 11 Protein Needs Minimum of 50 g daily, with all EAAs Individualized needs based on age and other factors Infants: 2.24 g/kg body weight (BW) Children: 1.5 g/kg BW Adults: 0.8 g/kg BW Older adults 1.0 to 1.2 g/kg BW Athletes: 1.0 to 2.0 g maximum per kg BW Increased needs also based on health parameters (e.g., protein status or states of increased demand, such as with burns) Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 12 Protein Deficiency Conditions Reduced albumin (<3.5 mg/dL) related to impaired body processes; (<2.8 mg/dL related to poor surgical outcomes with impaired wound healing and compromised immune system) Kwashiorkor: condition of protein deficiency Marasmus, or protein-calorie malnutrition (PCM) Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 13 Estimating Protein Content of Foods 1 oz meat (equals ¼ cup volume) = 7 g PRO 1 egg (¼ cup volume) = 7 g PRO ½ cup legumes, ¼ cup nuts, ¼ cup cheese (1 oz) and 1 tbsp peanut butter are counted as alternative to 1 oz meat 1 cup milk = 8 g PRO Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 14 Fat (Lipids) Constituent of body cell membranes: phospholipids Essential fatty acids needed for hormonal production (e.g., linoleic acid, an omega-6 fatty acid; alpha linolenic acid, an omega-3 fatty acid) Precursor of hormone-like compounds: eicosanoids Solid = saturated fats; liquid = unsaturated fats (monounsaturated and polyunsaturated) Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 15 Degree of Saturation Can Be Determined by Texture at Cold Temperature General amounts of saturated fats, monounsaturated fats, and polyunsaturated fats can be determined by appearance when fats are chilled. Note that solids are on the bottom of avocado and olive oils. Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 16 Food Label Guidelines Fat based on 30% kcal (65 g/2000 kcal) Saturated fat based on 10% kcal (20 g/2000 kcal) Trans fatty acids now listed; goal to have intake as minimal as possible Made from the addition of hydrogen to liquid oils; first commercial use of margarines and shortenings in the 1940s Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 17 Food Sources of Fat Found in germ portion of grains, some fruits (e.g., coconut, avocado, olives), and in whole milk (including butter), meats (including lard), nuts and seeds, egg yolks Omega-3 fatty acids (found in cold-water fish) essential for brain development; plant forms include flax, walnuts, canola oil Monounsaturated fats are preferred source for health (olive, canola oil and peanut oil, olives and most nuts, avocado) Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 18 Cholesterol A fatlike substance produced in the liver Found only in animal fat Not a kilocalorie source Necessary for normal body functioning Saturated fats can encourage excess production of cholesterol by the liver; unsaturated fats suppress the liver’s production of cholesterol; these processes are reflected in blood cholesterol levels To be discussed with review of Chapter 7 Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 19 Macronutrient Content of Food Exchanges (Per 1 Serving on Average) Food Serv CHO g GRAIN OR STARCH 1 oz 15 FRUIT ½c 15 MILK 1c VEG ½c MEAT 1 oz FAT 1 tsp SUG 1 tsp PRO g FAT g 2 0 15 8 5 avg 5 2 7 LUNCH PM DINNER H/S 5 4 54 19 15 Kcal 216 76 135 50% 18% 32% @427 AM 5 avg Total % kcal BKFST Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 20 Sample Menu Breakfast 1 starch: 1 milk: 1 fat: 1 sugar: Lunch 2 starch: 1 meat: 1 fat: 2 veg: 1 milk: 2 sugars: Dinner 1 starch: 2 fats: 3 meats: 2 veg: 1 fruit/sug: 1 milk: 1 slice toast 1 cup 2% milk 1 tsp butter 1 tsp jam 2 slices bread 1 oz turkey 1 tsp mayonnaise 1 cup mini-carrots 1 cup plain yogurt 2 tsp honey for yogurt ½ cup potato cooked in AM 1 fruit: ½ cup grapes PM 1 fruit: 1 orange H/S 1 fruit/1 milk: 1 cup strawberries with 1 cup 2% milk 2 tsp canola oil 3 oz ham 1 cup steamed cabbage ½ cup applesauce with 1 tsp cinnamon sugar 1 cup 2% milk Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 21 Menu Planning Using Food Exchanges Example: Goal 2000 kcal at 55% CHO, 15% PRO, 30% fat 2000 kcal × 0.55 = 1100 kcal/4 = 275 g CHO 2000 kcal × 0.15 = 300 kcal/4 = 75 g PRO 2000 kcal × 0.30 = 600 kcal/9 = 66 g fat To develop meal plan, start with number servings of primary CHO foods (starch, fruit, milk; each serving 15 g CHO) Goal of 275 g CHO/15 = 18 total servings of starch/fruit/milk; determine how many of each and start doing the math Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 22 18 Servings Starch, Fruit, Milk Food Serv CHO g GRAIN OR STARCH 11 165 FRUIT 4 60 MILK 3 PRO g FAT g 22 ~5 45 24 15 270 46 20 BKFST AM LUNCH PM DINNER H/S VEG MEAT FAT SUG Total kcal % kcal Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 23 Next Step: Add in Non-Starch Vegetables 2.5 cups vegetables = 25 g CHO (can substitute for 1 serving of primary CHO source (e.g., 1 starch) Revise sums of macronutrients Then determine amount of meat to meet remaining PRO needs for predetermined goal Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 24 See Evolve for More on Food Exchanges Complete food exchanges can be found in Evolve Any food can be included into the Food Exchanges that have similar macronutrient content, for example: 1 oz potato chips = 15 g CHO and 10 g fat or 1 oz potato chips = 1 bread and 2 fat servings For Menu Planning: Optimally low-fat/skim milk should be used in calculations, with emphasis on lean meats and unsaturated fats Elsevier items and derived items © 2010, 2007 by Saunders, an imprint of Elsevier Inc. 25