chapter
7
Nutrition
Dixie L. Thompson
Important Terms
•
•
•
•
•
Dietary Reference Intake
Recommended Dietary Allowance
Adequate Intake
Tolerable Upper Intake Levels
Acceptable Macronutrient Distribution
Range
Six Classes of Nutrients
•
•
•
•
•
•
Carbohydrate
Fat
Protein
Vitamins
Minerals
Water
Carbohydrate
• Glucose (C6H12O6) is the most important simple
sugar in the body.
• The primary storage form of carbohydrate in the
body is glycogen.
• Carbohydrate should be chosen based on nutrient
density.
• Dietary fiber is another important consideration
when choosing forms of carbohydrate.
• Glycemic index is used to describe how quickly a
food elevates the blood glucose level after
ingestion.
Fat
Important terms
–
–
–
–
–
–
–
Triglycerides
Phospholipids
Cholesterol
Lipoproteins
Saturated fats
Unsaturated fats
Trans fats
Protein
•
•
•
•
Amino acids combine to form proteins.
Protein serves a variety of roles in the body.
There are eight essential amino acids.
Ingesting 0.8 g of protein per kilogram of
body weight is generally adequate for
supplying the body’s needs.
• Protein can be supplied by both meat and
vegetarian selections. However, with a
vegetarian diet, care should be taken to
consume complementary proteins.
AMDR for Fat,
Carbohydrate, and Protein
Created from Food and Nutrition Board, Institute of Medicine, 2002, Dietary reference intakes
for energy, carbohydrates, fiber, fat, fatty acids, cholesterol, protein, and amino acids
(Washington, DC: National Academies Press).
Vitamins
• Vitamins are organic substances essential
to the normal functioning of the human
body.
• Fat-soluble vitamins are A, D, E, and K.
• Water-soluble vitamins are B and C.
• Antioxidant vitamins are thought to help
ward off disease. Beta-carotene, vitamin C,
and vitamin E are often praised for their
antioxidant qualities.
Minerals
• Minerals are inorganic elements that serve a
variety of functions in the human body.
• American adults consume inappropriate
amounts of calcium, iron, and sodium.
Minerals: Calcium
• Calcium is a mineral often ingested in
inadequate amounts by Americans.
• Adequate Ca2+ promotes bone health and
can prevent osteoporosis.
• Dairy products, dark green vegetables, and
some nuts are good sources of Ca2+.
Minerals: Iron
• Many Americans underconsume iron,
leading to iron-deficiency anemia.
• Men and postmenopausal women should
ingest 8 mg of iron each day
• Premenopausal women should ingest 18 mg
of iron each day.
• Good sources of iron are red meat and eggs
and vegetarian sources such as spinach,
navy and lima beans, and prune juice.
Minerals: Sodium
• Sodium is a mineral that many Americans
overconsume.
• Sodium is found in most processed foods.
• Sodium intake should be limited to no more
than 2,300 mg a day.
Water
• A person should ingest 1 to 1.5 ml of water
for each kilocalorie expended each day.
• The AI for men is 3.7 L · day–1 and for
women is 2.7 L · day–1.
Dietary Assessment
• Food logs can be useful in learning about a
person’s food intake.
• Clients should be educated about how to
properly complete food logs.
• Although a registered dietitian should be
consulted for specific dietary analysis and
instruction, a fitness professional who is
not a dietitian can often provide general
information on healthy eating.
Food Guide Pyramid
Reprinted, by permission, from V. Heyward, 2006, Advanced fitness assessment and exercise
prescription, 5th ed. (Champaign, IL: Human Kinetics), 235. MyPyramid from
www.mypyramid.gov.
Daily Values
• Daily values are used in food labeling to
help consumers understand the nutritional
quality of foods.
• Food labels must contain information about
total calories, fat (including saturated fat),
cholesterol, sodium, carbohydrate
(including dietary fiber), protein, and
various vitamins and minerals.
Lipoproteins and CVD Risk:
Understanding Cholesterol
It is important to differentiate
– HDL-C,
– LDL-C, and
– total cholesterol.
2001 NCEP Guidelines
for Ideal Values
• Total cholesterol < 200 mg · dL–1
• LDL-C < 100 mg · dL–1
• HDL-C > 60 mg · dL–1
Therapeutic Lifestyle Changes (TLC)
Diet
• Established by the NCEP
• Includes the following:
– Limiting total fat intake to 25% to 35% of calories
– Limiting saturated fat intake to 7%, polyunsaturated
fat intake to 10%, and monounsaturated fat intake to
20% of calories
– Limiting cholesterol intake to < 200 mg · day–1
– Limiting intake of trans fats
Hydration for Exercise
• 14 to 20 oz (350-600 ml) of water 2 hr before
exercise
• 7 to 10 oz (200-300 ml) 10 to 20 min before
exercise
• 6 to 12 oz (150-350 ml) every 15 to 20 min
during exercise
• 16 to 24 oz (475-700 ml) of fluid after
exercise for every pound (0.45 kg) of weight
lost
Protein Intake for Athletes
• Aerobic athletes who are training intensely
may benefit from consuming 1.2 to 1.4 g of
protein for each kilogram of body weight.
• A protein intake of 1.6 to 1.7 g per kilogram
of body weight may be needed for athletes
engaging in high-intensity, high-volume
resistance training.
• Protein intake is best obtained via a healthy
diet rather than amino acid supplements.
Ergogenic Aids
• Some products are not usually harmful but
provide no athletic edge.
• Some provide an edge but are banned by
regulatory agencies.
• Some lead to health risks that far outweigh
any potential increase in performance.
(continued)
Ergogenic Aids (continued)
• Higher-than-RDA levels of vitamins and
minerals do not appear to provide a
competitive edge.
• Creatine phosphate is a high-energy
compound that may enhance high-intensity
exercise performance. Long-term effects of
its use are unknown.
Carbohydrate and Athletes
• Generally, athletes should obtain 60% to
65% of their calories from carbohydrate.
• A diet containing 6 to 10 g of CHO per
kilogram of body weight is recommended
for athletes engaging in frequent,
exhaustive bouts of exercise.
• During long bouts of exercise, ingestion of
solutions containing 4% to 8% carbohydrate
(150-350 ml every 15-20 min) can help
maintain blood glucose concentration.
Carbohydrates and Athletes:
Carbohydrate Loading
• In preparation for competition, carbohydrate
loading can be useful.
• Carbohydrate loading consists of tapering
activity and ingesting large amounts of CHO
in the days leading up to competition.
Female Athlete Triad
• Female athlete triad is a condition characterized
by disordered eating, amenorrhea, and
osteoporosis.
• See chapter 17 for more information.