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Energy (cont.). Energy is the power used to do work or to produce heat or light. Energy can be changed from one form to another , but cannot be created or destroyed.
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Energy (cont.) • Energy is the power used to do work or to produce heat or light. • Energy can be changed from one form to another , but cannot be created or destroyed. • Living plants are able to convert solar energy into the chemical energy of carbohydrates, fats and proteins by a process called photosynthesis.
Energy (cont.) • Animals get their energy from the chemical energy contained in plants and other animals. • Energy maintains body functions, such as breathing, heartbeat, and heat production. • Energy is necessary for active movement; for example, muscle contraction. • Energy is used for growth and repair.
Carbohydrates • Carbohydrates in the form of glucose are the body’s primary source of fuel. • Sugar are considered to be simple carbohydrates and starches complex carbohydrates, although both end up as glucose after digestion. • Complex carbohydrates in the form of fruits, vegetables, and whole grains are often accompanied by vitamins and minerals as well as fiber. • Excess glucose is stored in the liver and muscles as glycogen or they are converted to fat for storage in fat cells.
Protein • Protein form on to the body’s main structural elements and are found in every cell. • Protein are important compontnts of muscles, connective tissue, skin, organs, blood, some hormones, antibodies, and enzymes.
Protein • Each protein is composed of varying combinations of 20 different building blocks called amino acids, many of which are provided to the body by the breakdown of dietary protein during digestion. • Nine of these amino acids are considered “essential” because they must be provided by the diet, while the 11 others are considered “nonessential” because they can be manufactured by the body. • A “complete protein” is a food that contains all of the essential amino acids, whereas an “incomplete protein” is a food that is low in one or more of the essential amino acids. • While most plant proteins are incomplete, a well-balanced vegetarian diet can provide the body with all needed amino acids.
Protein • Cells reassemble amino acids obtained from the diet and from the liver into proteins the body can use. • The average adult’s requirement for protein is considered to be 0.8 grams per kilogram of body weight and 1.6 grams per kilogram of body weight for power lifters.
Fats • Fat is a carrier of fat-soluble vitamins, provides essential fatty acids, is an important source of stored energy, and provides insulation against the loss of body heat. • No more than 10% of an individual’s daily calories should come from saturated fats, with no more than 30% from all fats.
Fats • Fatty acids are important components of fats. • Saturated fatty acids are usually solid at room temperature and have been associated with increased risk of cancer and heart disease when eaten in excess. • Monounsaturated fatty acids are liquid at room temperature and have been less associated with disease unless hydrogenated, as in margarine, which makes them solid at room temperature. • Polyunsaturated fatty acids, the primary fat found in seafood, are liquid or soft at room temperature. Polyunsaturated fatty acids, such as linoleic acid and alpha-linolenic acid, are considered essential fatty acids because they are required in the diet and used in the body for cell structure and producing some hormones. • Trans fatty acids are made when unsaturated fatty acids are hydrogenated to make margarines, shortening, and other solid fats.
Vitamins • Insufficient amounts of vitamins in the body will result in deficiency disorders that have specific symptoms. • Fat-soluble vitamins are stored in the body’s fat reserves and released as the body needs them. • Taking large doses can be toxic • Vitamins A (retinol), D (calciferol) E (tocopherol), K1 (phytonadione), K2 (menaquinones), K3 (menadione) are all fat soluble vitamins.
Vitamins • Water-soluble vitamins are not stored in great amounts in the body and must be replenished regularly. • Excessive water-soluble vitamins are excreted by the body in urine and do not reach toxic levels. • Water-soluble vitamins include vitamin B1 (thiamine hydrochloride), B2 (riboflavin), B6 (pyridoxine hydrochloride), C (ascorbic acid), B3 nicotinic acid (niacin), and nicotinamide (niacinamide), B12, and folic acid.
Minerals • Minerals are essential part of enzymes. They participate in regulating many physiological functions including transporting oxygen to cells, providing a mechanism for muscle contraction, and allowing nerve cells to conduct signals. • Most minerals are found in a variety of foods, although deficiencies can occur.
Water • Water is a most important nutrient, since a loss of just 2% to 3% of body weight will impair performance and a loss of 7% to 10% can be fatal. • The kidneys play an important role in regulating the body’s water balance. • Water helps regulate body temperature, transport nutrients, eliminate toxins and waste products, and maintain proper metabolism.
Water • To maintain proper hydration, six to eight glasses of fluids should be consumed each day; more when active. • Prehydrate by drinking a glass or two of fluids within an hour of exercise to help the body cope with immediate water loss due to perspiration, increased respiration and so on. • During and after the activity, drink as much liquid as possible. Restricting water intake during a practice or game is not only dangerous, it will hamper performance.
Water • Sports drinks • Today’s sports drinks contain sugar, minerals such as potassium and sodium, and water, and sometimes vitamins. Sports drinks with ephedra (ma huang) should be avoided due to dangerous side effects. • Sports drinks are particularly useful during long, hard workouts lasting more than one hour; otherwise water is more than adequate. • The real advantages of sports drinks come from their sugar content, allowing muscles to gain energy and delay fatigue.
Fiber • It is suggested that the normal diet consist of approximately 25 grams of fiber per day. • Fiber keeps the digestive tract running smoothly. Soluble fiber helps lower cholesterol, while insoluble fiber adds bulk to intestinal contents, preventing constipation and making it easier for the intestines to eliminate waste.
Daily Values • The Daily Value is a U.S. Food and Drug Administration guide to help consumers use food label information in planning their overall diet. • Daily Reference Values (DRVs) are based on the National Academy of Sciences’ 1998 Recommended Dietary Allowances and Dietary Reference Intakes (DRIs).
Daily Values • DRVs for energy-producing nutrients are based on the number of calories consumed per day, with 2000 calories per day as the reference. • The amount of fat is based on 30% of daily calories. • Saturated fat is based on 10% of calories. • Carbohydrates are based on 60% of calories. • Protein is based on 10% of calories. • Fiber intake is based on 11.5 grams per 1000 calories of fat, carbohydrates, and protein.
Daily Values • DRVs for some nutrients represent the uppermost limit that is considered desirable since excesses can cause health problems. • Total fat should be less than 65 grams. • Saturated fat should be less than 20 grams. • Cholesterol should be less than 300 milligrams. • Sodium should be les than 2400 milligrams.
The Food Guide Pyramid • The Food Guide Pyramid was designed by the U.S. Department of Agriculture (USDA) and the Department of Health and Human Services (HHS) as an easy way to show the groups of foods that make up a good diet, identifying proper proportions by the relative size of each group in the pyramid. • The Food Guide Pyramid also indicates the number of recommended daily servings for each group.
The Food Guide Pyramid • USDA and HHS Guidelines • Aim for a healthy weight. • Be physically active each day. • Let the Pyramid guide your food choices. • Choose a variety of grains daily, especially whole grains. • Choose a variety of fruits and vegetables daily. • Keep food safe to eat. • Choose a diet that is low in saturated fat and cholesterol and moderate in total fat. • Choose beverages and foods to moderate your intake of sugars. • Choose and prepare foods with less salt. • If you drink alcoholic beverages, do so in moderation.
