Eat for Life The Food and Nutrition Board's Guide to Reducing Your Risk of Chronic Disease (1992) / Chapter Skim
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3 The Food We Eat
3 The Food We Eat
Pages 33-56
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From page 33... ...
of fresh, steamed string beans. At least that is what your eyes see and your nose smells and your taste buds are about to experience.
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From page 34... ...
Others protein and minerals-are building materials. Still others vitamins and some trace elements and fatty acids are necessary for the chemical reactions that produce energy to move muscles or carry out the regulation of body metabolism.
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From page 35... ...
About two-thirds of the energy the body uses goes to keeping body temperature constant, repairing internal organs and skin, keeping the heart beating and lungs breathing, and ensuring the proper chemical balance inside and outside the body's cells. Most adults need between 1300 and IS00 calories a day just to stay alive without any physical activity at all.
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From page 36... ...
His wife, who weighs only 120 pounds, uses about 130 calories riding at his side. In general, you can figure your approximate daily energy needs using one of the following equations: For women: little physical activity: 960 + 3.8 times weight moderate activity: 1120 + 4.5 times weight regular exercise or manual labor: 1280 + 5.l times weight For men: little physical activity: 1080 + 5.5 times weight moderate activity: 1260 + 6.4 times weight regular exercise or manual labor: 1440 + 7.3 times weight For example, if our 150-pound man rides his bicycle every day for an hour, his daily energy need is a little over 2500 calories a day (1440 + 7.3 times 150 = 2535~.
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From page 37... ...
On the other hand, if you eat more calories on a given day than your body uses, the body uses the surplus energy to make fat molecules and stores them in the various fatty tissues in your body. That is why you gain weight when you regularly eat more calories than your body uses.
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From page 38... ...
l :~ :: ) : FIGURE 3.1 Comparison of calorie and nutrient content in 1 cup of ice cream, frozen yogurt, and ice milk.
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From page 39... ...
Maltose, consisting of two glucose molecules CH2OH H~O$OH OHM H OH CH2OH H~O; oH\OH H/ o HOCH2 O ~ H:>CH2OH OH H FIGURE 3.2 Structure for (a) monosaccharide glucose, and (b)
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From page 40... ...
In the digestive system, the large starch molecules are broken down, or digested, into individual glucose molecules. Glucose, not the original starch molecules, is absorbed from the digestive tract into the blood stream.
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From page 41... ...
The main difference between indigestible polysaccharides and starch is that in both soluble anc! insoluble fiber the chemical links that hold the inclividual molecules together as a chain are resistant to the processes of the human digestive system.
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From page 42... ...
In effect, the molecule is "saturated" with hydrogen atoms. Other saturated fatty acids found in food include stearic acid (~S carbon atoms)
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From page 43... ...
Since these fatty acids have more than one unsaturation, they are called polyunsaturated fatty acids. The polyunsaturated fatty acid with two unsaturations is called linoleic acid, and the polyur~saturated fatty acid with three unsaturations is called linolenic acid.
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From page 44... ...
if you count the carbon atoms starting at the omega end, you can see why linoleic acid is called an omega-6 fatty acid. If you read food labels, you have probably seen the term "partially hydrogenated vegetable oil." This means that hydrogen atoms have been added to unsaturated fatty acids by means of a chemical process known as hydrogenation.
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From page 45... ...
contains both saturated fatty acids and polyunsaturated fatty acids, but over half its fatty acids are monounsaturated, and most of that is oleic acid. ChoZesteroZ There are a number of substances in food that are not exactly fats but, like fats, do not mix with water.
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From page 46... ...
Medical experts consider a total serum cholesterol level below 200 milligrams per deciliter Meg/ to be desirable. Protein if carbohydrates and fat are the body's energy sources, then proteins are the body's building blocks.
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From page 47... ...
Enzymes and other biological molecules inside a cell reassemble the amino acids into those proteins that the cell needs. The body does not store significant amounts of amino acids, and so we have to eat protein regularly.
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48 EAT FOR LIFE Vitamin Functions Food Sources Fat-Soluble Vitamins Vitamin A Maintains normal vision and healthy skin and mucous membranes; necessary for normal growth and for repro duction Vitamin D Promotes calcium and phosphorus absorption from the intestines; in fluences bone growth Liver, butter, whole milk, egg yolks; margarine, skim milk, and certain breakfast cereals are fortified with vitamin A; the body also makes vitamin A from carotenoids, compounds present in dark-green leafy vegetables, yellow and orange vegetables, and fruit Liver, butter, fatty fish, egg yolks; milk is fortified with vitamin D Vitamin E Antioxidant that pre- Best sources are vegetable oils; vents cells from being also found in nuts, seeds, damaged by various whole grains, and wheat germ biochemical reactions that occur naturally Vitamin K Aids in blood clotting Best source is dark-green leafy vegetables; also found in cereals, dairy products, meat, and fruits Water-Soluble Vitamins Vitamin C Promotes growth of connective tissues; antioxidant Thiamin Aids in obtaining (Vitamin Be ~energy from carbo hydrates Citrus fruits, tomatoes, broccoli, green peppers, strawberries, melons, cabbage, and leafy green vegetables; vitamin C is destroyed when foods are overcooked or cooked in large amounts of water Meat, eggs, beans, and whole grains; enriched breads and cereals
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From page 49... ...
amino acids; aids in products, and fruits energy production from and vegetables protein Cobalamin Aids in DNA synthesis, (Vitamin Bit) and in energy production from fatty acids and carbohydrates; aids in production of amino acids Meat, milk and milk products, and eggs Folacin Aids in manufacture of Dark-green leafy vegetables, genetic material in cells; liver, and fruits aids in production of amino acl( .s Biotin Aids in energy production Egg yolks, liver, beans, and nuts Panto- Aids in energy produc thenic acid lion; aids in the manu facture of fatty acids; participates in a wide variety of other biochemical processes Most foods C and the eight B vitamins-thiamin, riboflavin, niacin, pyridoxine, pantothenic acid, biotin, folacin, and cobalamin.
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From page 50... ...
Salts are associations of positive and negative components called ions. Table salt, for example, is made from positively charged sodium ions and negatively charged chloride ions the chemical name for table salt is sodium chloride.
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THE FOOD WE EAT 51 TIC l Mineral Functions Food Sources Calcium The most abundant min- Dairy products, bones of eral in the body, 99 sardines and canned salmon, percent is in bones; is dark-green leafy vegetables, also important in muscle and lime-processed tortillas function Chloride Is a component of stomach Table salt, eggs, meat, acid; aids in maintaining and milk fluid balance in cells Chromium Works with insulin to Liver and other organ meats, promote carbohydrate brewer's yeast, whole grains, and fat metabolism and nuts Copper Aids in energy production; Liver, meat, whole grains, aids in absorption of iron and nuts from digestive tract; forms dark pigment in hair and skin Fluoride Strengthens teeth Some natural waters, and bones fluoridated water, and tea Iodine Is part of the thyroid Iodized table salt, ocean hormones that regulate seafood, dairy products, and metabolism commercially made bread Iron Aids in energy production; Meat, poultry, fish, nuts, helps to carry oxygen in whole and enriched grain the blood stream and products, and green muscles vegetables Magnesium Is necessary for nerve function, bone formation, and general metabolic processes Grain products, vegetables, dairy products, fish, meat, and poultry Manganese Aids in regulation of Cereals and most carbohydrate metabolism other plant foods and in general metabolic processes continued
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From page 52... ...
in this book the term "salt" will refer only to the compound sodium chloride. All other salts will be referred to by their chemical names.
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From page 53... ...
Archeologists have found evidence suggesting that the early human diet was about 35 percent meat and 65 percent plant food, though little of it was cereal grains. These people ate very little fat-they ate no dairy products and the meat they ate contained only about 4 percent fat and only low levels of sodium, but their diets were rich in clietary fiber, calcium, and vitamin C
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From page 54... ...
The amount of polyunsaturated fatty acids and monounsaturated 100 90 80 70 ° 50 40 So 20 102 o 1, , , , , 1 1 1 1910 1920 1930 1940 1950 1960 1970 1980 cl Carbobydrates ~ Fat Q Protein ~c _ ~__ Year FIGURE 3.7 Percent of calories from carbohydrate, fat, and protein in the U.S. food supply since 1909.
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From page 55... ...
Americans today eat about 385 mg of cholesterol a day, which is probably less than our grandparents ate because we con~m~ fewer e~ and less butter than they did. ,~ ~ ~ We also eat proportionately fewer carbohydrates than Americans did at the turn of the century; carbohydrates today account for 43 percent of the calories in the food supply, compared with 57 percent in 1909.
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From page 56... ...
56 E^T FOR LIFE today. But we now live longer primarily because of improved sanitation, antibiotics, and vaccinations infectious diseases are no longer the major killers they once were.
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