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Chapter 8 Nutrition and the Athlete
I. . Nutrition
A. Nutrition is defined as the process by which a living organism assimilates food and uses it for
growth and replacement of tissues.
B. Proper nutrition can reduce the likelihood of injury and allow the athlete to perform at a higher
level.
II. Energy
A. Energy is the power used to do work, or to produce heat or light.
B. Energy can be changed from one form to another, but cannot be created or destroyed.
C. Living plants are able to convert solar energy into the chemical energy or carbohydrates, fats, and
proteins through a process called photosynthesis.
D. Animals get their energy from the chemical energy contained in plants and other animals.
1. Energy maintains body functions, such as breathing, heartbeat, and heat production.
2. Energy is necessary for active movement; for example, muscle contraction.
3. Energy is used for growth and repair.
E. Energy is measured in calories. A calorie is the energy needed to raise the temperature of one
gram of water from 14.5 to 15.5 degrees Celsius (C).
1. One kilocalorie (kcal) equals 1,000 calories.
2. One food calorie is equal to one kilocalorie.
3. Carbohydrates and proteins contain four food calories per gram, while fats provide nine food
calories per gram.
III. Food Components
A. The human body must have a balanced diet consisting of carbohydrates, proteins, fats, vitamins,
minerals, water, and fiber.
B. Carbohydrates
1. Carbohydrates in the form of glucose are the body’s primary source of fuel.
2. Sugars are considered to be simple carbohydrates, and starches complex carbohydrates,
although both end up as glucose after digestion.
3. Complex carbohydrates in the form of fruits, vegetables, and whole grains are often
accompanied by vitamins and minerals, as well as fiber.
4. Excess glucose is stored in the liver and muscles as glycogen or converted to fat for storage in
fat cells.
5. Glucose levels in the blood are controlled by hormones, insulin and glucagon, produced in the
pancreas.
a. Insulin stimulates the body cells and liver to take glucose from the blood. Glucagon causes
glucose to be released into the blood as the liver converts glycogen back into glucose.
b. The balance of insulin and glucagon keeps blood-sugar levels relatively constant. Diabetes
is a condition of having little or no insulin produced by the pancreas.
6. About 45-50 percent of daily calories come from carbohydrates, mostly from complex
carbohydrate sources.
a. The daily diet should include six servings of grains, three servings of vegetables, and two
servings of fruits.
b. The average American adult gets about twice as many calories from simple carbohydrates
(sugars) than recommended.
7. The most basic sugar is the monosaccharide, which includes glucose, fructose, and galactose.
a. Disaccharides are composed of two monosaccharides, such as sucrose (table sugar), which
is composed of one glucose and one fructose chemically bonded together.
b. Polysaccharides, such as starch, glycogen, and cellulose, are composed of hundreds to
thousands of glucose molecules chemically bonded together.
C. Protein
1. Proteins form one of the body’s main structural elements and are found in every cell.
2. Proteins are important components of muscles, connective tissue, skin, organs, blood, some
hormones, antibodies, and enzymes.
3. 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.
a. Nine of these amino acids are considered “essential” because they must be provided by the
diet, while the 11 others are considered “nonessential” because the body can manufacture
them.
b. 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.
c. While most plant proteins are incomplete, a well-balanced vegetarian diet can provide the
body with all needed amino acids.
4. The average adult’s requirement for protein is considered to be 0.8 grams per kilogram of body
weight.
D. Dietary fat
1. Fat is a carrier of fat-soluble vitamins, provides essential fatty acids, and is an important source
of stored energy, and provides insulation.
2. Fatty acids are important components of fats.
a. 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.
b. 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.
c. 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-linoleic 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.
d. Trans fatty acids are made when unsaturated fatty acids are hydrogenated to make
margarines, shortening, and other solid fats.
E. Vitamins
1. Vitamins are complex organic substances that the body needs in small amounts for a variety of
different body functions.
2. Insufficient amounts of vitamins in the body will result in deficiency disorders that have
specific symptoms.
3. Fat-soluble vitamins are stored in the body’s fat reserves and released, as the body needs them.
a. Taking large doses can be toxic.
b. Vitamins A (retinol), D (calciferol), E (tocopherol), K1 (phytonadione), K2 (menaquinones),
and K3 (menadione) are all fat-soluble vitamins.
4. Water-soluble vitamins are not stored in great amounts in the body and must be replenished
regularly.
a. Excess water-soluble vitamins are excreted by the body in urine and do not reach toxic
levels.
b. Water-soluble vitamins include vitamin B1 (thiamine hydrochloride), B2 (riboflavin), B6
(pyridoxine hydrochloride), C (ascorbic acid), nicotinic acid (niacin) and nicotinamide
(niacinamide), B12, and folic acid.
F. Minerals
1. Minerals are essential parts 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.
2. Most minerals are found in a variety of foods, although deficiencies can occur.
G. Water
1. Water is a most important nutrient, since a loss of just 2-3 percent of body weight will impair
performance, and a loss of 7-10 percent can be fatal.
2. The kidneys play an important role in regulating the body’s water balance.
3. Water helps regulate body temperature, transport nutrients, eliminate toxins and waste
products, and maintain proper metabolism.
4. To maintain proper hydration, six to eight glasses of fluids should be consumed each day, more
when active.
a. 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, increase, respiration, and so on.
b. During and after activity, drink as much liquid as possible. Restricting water intake during
a practice or game not only hampers performance but is dangerous.
5. Sports Drinks
a. Today’s sports drinks contain sugar, minerals such as potassium and sodium, water, and
sometimes vitamins. Sports drinks with ephedra (ma huang) should be avoided due to
dangerous side effects.
b. Sports drinks are particularly useful during long, hard workouts lasting more than one hour,
otherwise, water is more than adequate.
c. The real advantages of sports drinks come from their carbohydrates, sugar, and other energy
compounds that help feed muscles and delay fatigue.
H. Dietary fiber
1. Dietary fiber is the indigestible component of plant material that humans consume.
2. Fiber keeps the digestive tract running smoothly. Soluble fiber helps lower cholesterol levels.
Insoluble fiber adds bulk to intestinal contents, preventing constipation and making it easier
for the intestines to eliminate waste.
3. It is suggested that the normal diet consist of approximately 25 grams of fiber per day.
IV. Daily Values
A. The Daily Value is a United States Food and Drug Administration guide to help consumers use
food label information in planning their overall diet.
B. Daily Reference Values (DRVs) are based on the National Academy of Sciences’ 1998
Recommended Dietary Allowances and Dietary Reference Intakes (DRIs).
C. DRVs for energy-producing nutrients are based on the number of calories consumed per day, with
2,000 calories per day as the reference.
1. The amount of fat is based on 30 percent of daily calories.
2. Saturated fat is based on 10 percent of calories.
3. Carbohydrates are based on 60 percent of calories.
4. Protein is based on 10 percent of calories.
5. Fiber intake is based on 11.5 grams per 1,000 calories.
D. DRVs for some nutrients represent the uppermost limit that is considered desirable, since excesses
can cause health problems.
1. Total fat should be less than 65 grams.
2. Saturated fat should be less than 20 grams.
3. Cholesterol should be less than 300 milligrams.
4. Sodium should be less than 2,400 milligrams.
V. The Food Guide Pyramid
A. The Food Guide Pyramid was designed by the United States Department of Agriculture (USDA)
and the Department of Health and Human Services (HHS) as an easy way to educate people about food,
nutrition, and exercise choices.
B. The Food Guide Pyramid indicates the amount of food group needed to stay healthy.
C. USDA and HHS Guidelines
1. Consume a variety or nutrient-dense foods and beverages within the basic food groups.
2. Limit the intake of saturated and trans fats, cholesterol, added sugars, salt, and alcohol.
3. Meet recommenced intakes within energy needs by adopting a balanced eating pattern.
4. Maintain body weight in a healthy range.
5. Engage in regular physical activity and reduce sedentary activities (60-90 minutes daily).
6. Consume a sufficient amount of fruits and vegetables while staying within energy needs.
7. Consume three or more ounces of whole grain products each day.
8. Consume three cups of fat-free or low-fat milk or equivalent milk products each day.
9. Consume less than 10 percent of calories from saturated fatty acids and less then 300mg/day of
cholesterol, and keep trans fatty acid consumption as low as possible.
10. Choose and prepare foods and beverages with little added sugar or sweetener.
11. Consume less than 2,300mg (approximately 1 teaspoon of salt) of sodium per day.
D. Other cultures base their food pyramids on foods commonly eaten by their people, just as the Food
Guide Pyramid from the USDA is based on American preferences. All food pyramids, however,
emphasize eating plenty of whole-grain products, vegetables, and fruits, and all recommend
physical activity.
E. Food groups
1. Breads, cereals, rice, and pasta make up the bottom of the pyramid, providing complex
carbohydrates, vitamins, minerals, and fiber.
2. Vegetables, the next level up, provide vitamins A, C, folate, and minerals such as iron and
magnesium, and are a good source of fiber.
3. Fruits provide vitamins A, C, and minerals like potassium.
4. Meat, poultry, and fish provide protein, B vitamins, iron, and zinc.
5. Milk products provide protein, vitamins, and minerals such as calcium.
6. Fats, oils, and sweets – the top and smallest part of the pyramid—while necessary in small
amounts, should be limited, even though some nutrients found here are important.
VI. Nutritional Quackery
A. New dietary supplements are marketed each day, often developed and sold without any scientific
research to support their claims of benefits, and without proving any harmful side effects. These
are treated by the FDA as foods and are not evaluated for safety and effectiveness.
B. Individuals and companies promoting these dietary supplements prey on the innocent,
unsuspecting athlete who is eager for an edge on the competition or who may be looking for an
easy alternative to hard work and training.
C. Before taking any product, the athlete should check with someone who has nutritional training for
advice. The best protection against nutritional quackery is to be an informed consumer.
VII. Making the Weight
A. One of the most important aspects of fitness and athletic performance is controlling weight.
B. Gaining weight without gaining fat is only possible through weight-training programs. Without a
weight-training program and increased energy expenditure, excess caloric intake will be converted
to fat.
C. Losing weight can be accomplished by restricting calorie intake, or through exercise, or both.
1. Minimum caloric intake for females should not go below 1,000-1,200 calories per day; 1,2001,400 calories for males.
2. The best way to lose weight is through a combination of a moderate diet and exercise.
3. Exercise can increase cardiorespiratory endurance and result in a gain in strength and increased
flexibility – all positive changes to a person’s overall health.
4. It is always important to check with the family physician before beginning any weight-loss or
weight-gain program.
VIII. Disordered Eating
A. Disordered eating patterns include anorexia nervosa, bulimia nervosa, and binge eating, all
dangerous behaviors that can result in serious health problems.
B. Of all athletes with disordered eating behaviors, 25 percent are male, a condition now termed
manorexia.
C. The Female Athlete Triad
1. The female athlete triad consists of disordered eating, amenorrhea, and osteoporosis, and is
especially prevalent among gymnasts, figure skaters, divers, dancers, swimmers, and runners.
2. Symptoms include eating alone, trips to the bathroom during and after meals, use of laxatives,
fatigue, anemia, depression, and eroded tooth enamel due to frequent vomiting.
3. Treatment involves education, nutrition, determining contributing factors, and being under the
care of a medical specialist trained in disordered eating.
D. Anorexia nervosa
1. Anorexia nervosa is a psychophysiological disorder, usually occurring in young women,
characterized by an abnormal fear of becoming obese, a distorted self-image, a persistent
unwillingness to eat, and severe weight loss.
2. Self-induced vomiting, excessive exercise, malnutrition, and amenorrhea often accompany the
disorder.
3. Symptoms include at least a 15 percent loss of normal body weight, loss of appetite, loss of
menstruation, fatigue and dizziness, constipation, and abdominal pains.
4. Complications connected with anorexia nervosa are starvation, dehydration, muscle and
cartilage deterioration, osteoporosis, irregular or slow heartbeat, and heart failure.
E. Bulimia
1. Bulimia is an eating disorder, common among women of normal or nearly normal body weight,
characterized by episodic binge eating followed by feelings of guilt, depression, and selfcondemnation.
2. Bulimia is often accompanied with measures taken to prevent weight gain, such as self-induced
vomiting, the use of laxatives, dieting, or fasting.
3. Symptoms include fluctuations in weight, dental cavities from vomiting stomach acid,
dehydration, fatigue and dizziness, constipation and abdominal pains, swelling of salivary
glands, and irregular or absent menstruation.
4. Complications associated with bulimia include stomach ulceration, bowel damage,
inflammation or tearing of the esophagus, laxative addiction, tingling hands and feet, and
electrolyte imbalances that can lead to heart failure.
IX. Special Diets
A. Before embarking on any special diet, the athlete should talk with the family physician,
nutritionist, certified athletic trainer, or health professional.
B. Pregame meal
1. Energy for the game actually comes from muscle glycogen stores that are built up by
consuming high carbohydrate meals every day, not just the pregame meal.
2. The pregame meal helps supplement muscle glycogen stores and prevents a low blood-sugar
level, with its accompanying lightheadedness, fatigue, and low concentration.
3. The pregame meal should be eaten three or four hours before the game, with foods high in
carbohydrates and fluids. Grain products, vegetables, and fruits are best choices because they
are digested quickly and are readily available for fuel.
4. Protein intake should be moderate, and foods that are high in fat, sugar, or contain caffeine
should be avoided altogether.
X. Calculating “Ideal” Weight for Athletes
A. Body mass index (BMI) is a reliable indicator with some limits of total body fat. BMI = Weight
(lb.) ÷ Height (in.) ÷ Height (in.) x 703
B. Normal weight should have a BMI range of 18.5 to 24.9, overweight 25 to 29.9, and obesity 30 or
greater.
C. Another method is to use a weight chart that compares others of the same age and gender, based on
a national average.