Transcript Chapter 6

Chapter 6
Nutritional Considerations
Nutrition
• Diet influences every aspect of sports participation
• *
• Recovery from training and competition
• *
• Recovery from injury (to some extent, the likelihood of injury)
• Certified athletic trainers are typically more knowledgeable about
nutrition than coaches.
• Coaches and athletes often lack adequate nutrition information
and incorporate unfounded nutritional practices into training
programs.
• 6 classes of nutrients that we will cover in this
chapter
• Macronutrients (required in large amounts)
1. Carbohydrates
2. *
3. Proteins
• Micronutrients (required in small, or trace amounts)
4. *
5. Minerals
6. *
Carbohydrates
Carbohydrates (CHO) provide energy for high-intensity
exercise.
• Specific forms of CHO used within the body are blood
glucose and glycogen (the storage form of glucose)
found in the liver and skeletal muscle.
• A carbohydrate is made up of a carbon, hydrogen, and
oxygen atom, with the number of carbon atoms
ranging from 3 to 7.
Categories of Carbohydrates
1. Monosaccharides (the simplest form, single molecule)
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•
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*
*
Galactose
2. Disaccharides (2 monosaccharide molecules combined)
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Lactose (milk sugar)
*(most common sugar in the diet)
*
3. Polysaccharides (10 to thousands of monosaccharides
combined)
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Glycogen
*
Cellulose
Carbohydrates
• The most common forms of dietary CHO
intake are from simple sugars (foods high in
fructose) such as soft drinks, candy, and high
sugar cereal.
• High in caloric content, these foods provide
little in the way of other nutrients, and are
therefore called “empty calories”.
Sources of Carbohydrates
1. *– a superior form of CHO.
• The CHO in these foods is in the form of starch (a complex
carbohydrate)
• Complex Carbohydrates often contain dietary fiber which
may lower cholesterol absorption and is beneficial to the
digestive system.
2. *
• Provide CHO in the form of fructose (monosaccharide) is
sweeter than sucrose, and it “does not stimulate pancreatic
insulin secretion” and therefore “helps to stabilize bloodglucose and insulin levels”.
• *
Carbohydrates and Your Diet
• CHO in the diet should range between 60% and 70%
of the total calories consumed daily (depending on the
exercise intensity)
• Regardless of the type of CHO, they all provide
approximately *
• A kilocalorie (kcal) is the energy equivalent required
to raise the temperature of 1 kilogram of water by 1
degree Celsius)
• *
Carbohydrate (Glycogen) Loading
• Where is the majority of CHO stored in the body? In the skeletal
muscles and liver as glycogen!
• Therefore, it is to the athlete’s advantage physiologically to
increase the amount of stored glycogen prior to competition!
• *
• Typical regime begins approx 1 week prior to competition
• High-intensity exercise, high protein, low CHO diet for the
first 4 days
• Days 5-7 consist of high CHO and normal protein diet
• High CHO meal is consumed on the day of competition
Fats (Lipids)
Fats (lipids) are needed for a variety of reasons:
• Provide energy for muscle contraction
• *
• *(kidneys and heart)
Dietary fats are either simple or complex
• Consist of Carbon, Hydrogen, and Oxygen atoms
(like CHOs) but the ratio of Hydrogen to Oxygen is
far greater in fats
• *
Simple Fats
• Consist of 2 components (glycerol and a fatty acid)
• Can be either saturated or unsaturated
• Saturated (all the available bonding sites on the fatty acid
molecule are occupied by a hydrogen atom.
• Most saturated fats are from animal sources (beef, pork,
poultry, and dairy products)
• *
• Unsaturated (prevents all available bonding sites from being
occupied by a hydrogen atom)
• *
• Recommended that the majority of fats consumed be
unsaturated to avoid the problems attributed to excessive
consumption of saturated fats related to cardiovascular
disease
Fats in Your Diet
• Fats in the diet should be * of the total calories
consumed daily.
• Recommended that saturated fats make up only * of
total fats
• Regardless of the type of fat, they all provide
approximately *
• The available amount of energy in the form of stored
body fat is significantly greater than what is available
from CHO.
• *
Energy and Consumption of Fat-Containing
Foods
FOOD
SERVING SIZE
ENERGY (kcal)
Fat (g)
Milk, whole
8 oz
150
8.2
Milk, 1%
8 oz
102
2.6
Peanut Butter
1 tbsp
111
9.1
Cookies, Oreos
3 cookies
160
7.0
Apple
1 medium
81
0.5
Avocado
1 medium
324
29.0
Strawberries
1 cup
45
1.0
Ground Beef
3 oz
231
15.5
Chicken Breast
3 oz
140
3.1
Proteins
Proteins also contain carbon, hydrogen, and oxygen
molecules, but also contain nitrogen (makes them
unique)
• Assembled by combining amino acids; 20 specific
amino acids required in the body to produce
thousands of proteins
• *
• Muscle protein is used as an energy source
during prolonged exercise; produces as much as
10% to 15% of the energy requirements
• *
Proteins
• The body builds proteins from the amino acids that
come from the protein consumed in the diet
• Of the 20 amino acids required to make the body’s
protein, 8 cannot be synthesized by the body and
must be ingested in the diet
• 8 essential amino acids:
1.
2.
3.
4.
5.
6.
7.
8.
Isoleucine
*
Lysine
*
Phenylalanine
*
Tryptophan
*
Protein Supplementation
Protein supplementation is not recommended because
the excess can:
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• NO scientific evidence that protein supplements
enhance muscles (not regulated by the FDA)
• During intense training, 1.2 to 1.8 grams of protein/kg
body weight are recommended.
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Vitamins
Vitamins have various functions:
1. Help regulate metabolism
2. *
3. Some serve as antioxidants (protect structures such
as cell membranes from the damaging effects of free
radicals that are released during vigorous exercise)
• *
Types of Vitamins
Water-Soluble Vitamins
• C
• *
• B2
• B6
• B12
• *
• Folic Acid
• *
• Pantothenic Acid
Fat-Soluble Vitamins
• A
• *
• E
• *
How Many Vitamins??
• * vitamins are not stored in the body and excess amounts
are excreted via the kidneys and urine
• * vitamins are stored in the fat tissues in the body. Excess
consumption can result in buildup and an eventual toxic
reaction to the stored vitamin
• *
• Athletes consuming a balanced diet are most likely getting
adequate amounts of vitamins
• *
Minerals
Minerals are elements needed for various body
functions.
• * is most prevalent mineral in body.
• There is no scientific evidence to support taking
minerals in excess of RDA for performance.
• Athletes who do not eat a balanced diet should
be advised to include a vitamin and mineral
supplement.
•*
Calcium
• Why is calcium so important?
• Normal bone health
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• Osteoporosis
• Who is at risk?
• Female athletes in aerobic running
• *
• Where do you find calcium?
• Dairy products
• *
• RDA for adolescent females is 1500mg/day
Water (H2O)
Water is necessary for human performance, as well as
survival.
• Necessary for cellular function
• *
• Necessary for elimination of waste products
Housed in 2 general locations: intracellular,
extracellular
Water
• At rest, the water requirement for an adult is approx *
• During exercise or high heat/humidity environments,
the daily consumption can increase to 5-10L
• During exercise, a significant amount is lost to
metabolic heat
• Sweat evaporation from the skin can easily result in an
hourly water loss of 2L or more for each hour of
exercise
• What happens if you don’t replace the water you lost?
Dietary Habits of Athletes
• Eck’s study of 43 university football players
indicated their diets were 34.7% CHO,
17% protein, and 42% fat.
• Recommended proportions are 45%–70%
CHO, 12%–15% protein, and 20% fat.
• A high protein requirement as a
prerequisite to athletic success is a myth.
Dietary Habits of Athletes
Conclusions
• Many athletes do not consume proper
proportions of protein, CHO, and fat.
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• Athletes in sports that require lean bodies
tend to eat diets with insufficient calories.
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• Most athletes’ diets are deficient in
important minerals, i.e., calcium, iron, &
zinc.
Diet and Wrestling
Wrestlers often follow unhealthy
weight loss procedures to
compete in lighter category.
• *
• Dehydration occurs through
the use of laxatives and
diuretics, fluid restriction,
artificially induced sweating,
and starvation.
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Wrestling (cont.)
Short-term effects of repeated
bouts of extreme weight loss
include:
• Increased blood
viscosity.
•*
• Kidney and liver
problems.
• *.
Long-term effects may include
interference with normal growth
and development.
Wrestling Minimum Weight
Project (WMWP)
Wisconsin instituted WMWP in 1989.
• Weight loss must be no more than 3 lbs.
of weight loss/week.
•*
• Testing of athletes, along with nutrition
education for coaches, was done by
trained volunteers.
WMWP (continued)
The NFSH has developed a national
wrestling rule #1-3-1 that states:
“A medical professional should…establish
a minimum (wrestling) weight through…
checking body fat and hydration. The
recommended minimum body fat should
not be lower than 7%.”
What Can the Coach Do?
Coaches are an important source of
nutrition information.
• People planning to enter the
coaching profession should take at
least one basic college nutrition
course.
• Attend in-service meetings,
professional conferences, or
community education programs in
sports nutrition.
• *
What Can the Coach Do? (cont.)
• Locate nutrition experts,
including dietitians, university
nutrition faculty, or sports
medicine staff.
• Have athletes keep a record
of their diet that is reviewed
periodically by a person
knowledgeable in nutrition.
• *
General Dietary Guidelines for
Athletes
All sports nutrition programs should have 3 goals:
• Nutritional maintenance and development during
training to ensure adequate recovery between
training sessions
• *
• Nutrition during competition
Nutrition During Training
Recommendations include:
• 10% to 15% of calories from protein, 30%
from fat, and the remainder from CHO.
• *
• Little need for vitamin/mineral supplements
if diet is well balanced.
• Using simple terms when educating young
athletes about nutrition.
MyPyramid, www.MyPyramid.gov
Pre-competition Diets
• Avoid eating meals 2 to 3 hours before
event (digestion takes 2 to 3 hours to occur
– foods eaten just before an event will do
nothing for performance)
• *
• Diet should consist of low-fat, easily
digestible foods
• Liquid meals increase hydration and are
less likely to cause bloating or “heavy”
feeling than solid meals.
• Foods should provide * grams of CHO or 3
to 5 grams/kg of body weight.
Nutrition During Competition
• The body has limited capacity for
storing glycogen, and athletes may
deplete those supplies before the
event is over
• *
• 2 hours can deplete the stores in
both the liver and muscle (“hitting
the wall”)
• Most sports drinks provide CHO
levels of *
Nutrition for Recovery
• Glycogen depletion can occur 2-3 hours after
completion of exercise (80% of VO2 max)
• *
• CHO intake of 0.5-0.7g/lb body mass during the first
30 minutes of recovery and again every 2 hours for 46 hours is adequate to replace glycogen stores
• *
• www.scandpg.org
Weight vs. Fat Management
• Body weight consists of water, fat, and lean tissue.
• *
• When athlete fails to consume enough calories to
meet needs, fat is metabolized for energy.
• Severe caloric restrictions (fasting) result in protein
breakdown (reduction of lean muscle mass = loss of
performance.
• Most active females have a body fat *
• Most active males have a body fat *
Minimal Competitive Weight
• Athletes should only weigh themselves
once/week at the same time of day and
after going to the bathroom.
• Males should have at least * of their
total body composition in the form of
fat.
• Females should have a minimum of
* of their total body composition as fat.
• Determine body fat % by using skin
calipers
Minimal Competitive Weight (MCW)
• Fat weight = body weight x body fat %
• LBW = total body weight – fat weight
• MCW = LBW ÷ 0.95
An athlete weighs 135 lbs and has 14% body fat.
• Fat weight = 135 x .14 = 18.9 lbs
• LBW = 135 – 18.9 = 116.1
• MCW = 116.1 ÷ 0.95 = 122.2 lbs
Nutrition and Injury Recovery
Weight gain can occur with forced inactivity due
to injury.
• Recommend cross training during recovery.
• Runners can ride stationary bikes or run in
swimming pools.
• Maintains aerobic fitness while burning
excess calories.
• *
Supplements and Ergogenic Aids
• Supplements have become very popular
with athletes of all calibers.
• Supplements can be divided into two
categories: legal and illegal.
• Legal supplements: *, creatine, amino
acids, and *.
• Illegal supplements: *, androstenedione,
EPO, GHB, *.
Creatine
• Creatine is found naturally in the cells
and is used to convert ADP into ATP
(energy)
• Creatine has been found to be more
helpful for athletes who use short bursts
of energy than for endurance athletes.
• Produces an increase in energy at the
cellular level which allows the athlete to
train for longer periods of time.
• There are many published studies on
creatine use that report conflicting
results.
Quick Reference
• 1kg = 2.2 lbs
• Protein requirements:
• 10-20% of total caloric intake
• 0.8g/kg (normal)
• 1.2-1.8g/kg (vigorous exercise)
• Carbohydrate requirements:
• 60-70% of total caloric intake
• 1g/kg (normal)
• 5-7g/kg (vigorous exercise)
• Fat requirements:
• No more than 30% of total caloric intake
• 0.8g/kg