Transcript Nutritional Considerations

Chapter 6
Nutritional
Considerations
Nutrition
• Diet influences every aspect of sports
participation.
• Certified athletic trainers and strength &
conditioning coaches are most
knowledgeable about nutrition.
• Coaches and athletes often lack adequate
nutrition information and incorporate
unfounded nutritional practices into training
programs.
Knowledge of Nutrition
• Recent studies (Jacobson et al., 2001; Froiland et al.,
2004)
• Demonstrated that athletes may be
receiving better nutritional education from
more reliable sources.
• But there is still education to be done
because Jacobson et al (2001) reported
that only 55% of college athletes
received nutritional advice always or
often during their college careers.
Eating for Sport Performance
• Academy of Nutrition and Dietetics indicates
that eating properly will:
• help you train longer and at a higher intensity
• delay the onset of fatigue; promote recovery
• help your body adapt to workouts
• improve body composition and strength
• enhance concentration
• help maintain healthy immune function
• reduce the chance of injury
• reduce the risk of heat cramps and stomach
aches.
Overview of Nutrients
Macronutrients
• Carbohydrates
• Fats (Lipids)
• Protein
Micronutrients
• Vitamins
• Minerals
Water
Caloric Intake (Rest + Activity)
(Sammarone Turocy et al., 2011)
• Caloric intake should be based on the body
weight goal.
• Total caloric intake should be determined by
calculating the basal metabolic rate (BMR)
and the energy needs for activity.
• The metabolic qualities of the activity should
be considered when calculating the need for
each energy-producing nutrient
(carbohydrates, fats, proteins).
Carbohydrates
• Carbohydrates (CHO) provide energy for highintensity exercise
• Experts recommend 60% to 70% of daily
calories be supplied by CHO.
• Each gram of CHO provides 4 kilocalories.
• Average person stores approximately 1500 to
2000 kcals of CHO, the majority of which is in
the form of muscle and liver glycogen. Small
portion available as blood glucose.
• CHO are now classified on how fast they are
oxidized. Known as the Glycemic Index.
Carbohydrates
• CHO derived from plant sources, primarily
grains, seeds, fruits, and vegetables.
• Simple CHO – monosaccharides
• Typically stimulate insulin release and blood
glucose fluctuations.
• Foods containing are high caloric and often
referred to as empty calories.
• Complex CHO – polysaccharides
• Whole-grain cereals & breads, vegetables,
and fruits.
• Dietary fiber (indigestible CHO) essential for
digestion.
Carbohydrates
• Simple and complex CHO are suitable to describe
foods, but these do not represent the way they are
hydrolyzed and absorbed by the body.
• Low Glycemic Index CHO
• Cause a steadier rise and decline in blood
glucose and insulin. Best for weight management
and overall diet.
• High Glycemic Index CHO
• Typically result in a large and rapid rise in blood
glucose and insulin, followed by a rapid decrease
in blood glucose. Best for refueling after event.
Carbohydrate Loading
• Carbohydrate loading can benefit athletes involved in
aerobic sports, especially activities lasting 60 minutes
or more.
• Properly executed regimen of CHO loading can boost
the level of stored glycogen.
• 1 week prior to the competition and includes a gradual
tapering of physical activity accompanied with a slight
increase in CHO ingestion.
Fats (Lipids)
• Fats are needed for energy, insulation, and
protection of organs.
• Fatty acids and glycerol make up fats.
• Fatty acids: Saturated and Unsaturated
• Experts recommend that fats compose 30% or
less of total calories. 10% saturated
• Each gram of fat supplies 9 kilocalories.
Fats
• Saturated - all of the available bonding sites
on the fatty acid molecule are occupied by a
hydrogen atom. Derived from animal sources
(i.e., beef, pork, poultry, and dairy products).
Generally solid at room temperature.
• Unsaturated fats are structured in such a way
as to prevent all of the available bonding sites
from being occupied by a hydrogen atom.
Plant based. Generally liquid at room
temperature.
Proteins
• Proteins are needed for tissue construction, enzyme
reactions, and energy during prolonged exercise.
• Experts recommend that proteins compose 10-15%.
• Each gram of protein supplies 4 kilocalories.
• Proteins are composed of amino acids
• 20 different amino acids are used to make
thousands of proteins.
• 8 are essential amino acids, which cannot be
synthesized by the body and must be ingested in
the diet.
Proteins
• Sources include eggs, meats, dairy products,
legumes, or grains.
• Athletes who are on vegetarian diets must take care to
eat foods in the correct combination to provide all of
the essential amino acids.
• A solution to the problem is for such athletes to
include either eggs (ovolactovegetarian), milk
products (lactovegetarian), or both to ensure
adequate supplies of essential amino acids.
Protein Supplementation
• Protein supplementation is not recommended
because:
• Increase saturated fat in the diet
• Overstress the liver and kidneys.
• NO scientific evidence that protein supplements
enhance muscles.
• During intense training, 1.2-1.8 grams protein/kg body
weight are recommended.
• 0.83-1.2 g/kg for sedentary or light exerciser
• Normal diet provides adequate protein consumption
for intense training.
Vitamins
• Vitamins have various functions
• Regulate biochemical reactions (energy metabolism
and cell and tissue generation)
• Serving as antioxidants that protect cell structure.
• Vitamins contain no caloric value and a balanced diet.
supplies the RDA.
• There are water- and fat-soluble types of vitamins.
• Water soluble: Vitamins C, B1, B2, B6, B12, niacin,
folic acid, biotin, and pantothenic acid.
• Fat soluble: vitamins A, D, E, and K.
Minerals
• Minerals are elements needed for various body
functions.
• Provide structure, help maintain normal heart
rhythm, assist muscle contractility, promote neural
conductivity, and regulate metabolism.
• There is no scientific evidence to support taking
minerals in excess of RDA for performance.
• But endurance athletes may be at an increased risk
of iron or calcium deficiency
• Iron and Calcium RDAs
• Iron:10 mg for males and 18-20 mg for females
Calcium: 1500 mg
Vitamins and Minerals
Athletes who do not eat a balanced diet
should be advised to include a vitamin and
mineral supplement.
• A convenient method of
supplementation is a daily multivitamin
• Megadoses of vitamins/minerals should
be avoided and could result in severe
consequences
Water (H2O)
• Water is necessary for human performance, as
well as survival.
• Adult water requirement at rest is approx. 2.5 liters
daily, but it can increase to 5–10 liters during
heavy exercise, especially in high temperature and
humidity.
• Water lost during exercise needs to be replaced to
maintain body’s fluid balance.
• A reduction of body weight of 2-5% can impair
function.
• Current recommendations are for every 1 lb lost
due to sweating, 20-24 oz. of water be
consumed.
Nutritional Knowledge: The
Research
• Athletes are largely uneducated regarding proper
nutrition, even though they understand the importance
of adhering to a quality diet. (Torres-McGehee et al., 2012)
• Sources information come from family members
(32%), fellow athletes (32%), athletic trainers (ATs;
30%), dietitians (30%), coaches (28%), and TV, radio,
or the Internet (10%) to obtain their information. (Froiland
et al., 2004)
• Hilton (2005) reported that 70% of university athletes
(n = 345) are falling short of their daily caloric needs.
Female Athletes
• As more women become involved in organized
sports, concerns have been raised regarding their
special nutritional considerations.
• Especially those involved in aesthetic sports that
place an emphasis on being lean, such as
gymnastics, diving, and dancing.
• Greenleaf and colleagues (2009) determined that
54% of college athletes were dissatisfied with
their current weight.
• Clinical disordered eating: 47% in lean sports;
20% in “non-lean” sports
Endurance Sports
athletic energy deficit Athletes not consuming
enough calories. A new concern emerging in
athletics.
• Athletes with athletic energy deficit will be unable
to support vital body functions including bone
growth.
• With insufficient energy post exercise repair is
inhibited, hormones affected, amenorrhea and
slower/poor bone growth.
• Other adverse health-related consequences
include: depression, lethargy, attention deficits,
sleep disorders, and increases in body fat.
Wrestling
• Wrestling is one of only a few sports that match
participants on the basis of weight.
• Wrestlers often follow unhealthy weight loss
procedures to compete in lighter weight
categories.
• Rapid weight loss occurs via dehydration.
• Dehydration occurs through the use of
laxatives and diuretics, fluid restriction,
artificially induced sweating, and
starvation.
• No definitive proof that such tactics actually
present an advantage.
Wrestling
• Short-term effects of repeated bouts of extreme
weight loss include: (Nelson, 1989; Williams, 1992)
• Increased blood viscosity
• Blood clots
• Kidney, liver and pancreas problems
• Ulcers
• Speculative long-term effects may include
interference with normal growth and
development.
Wrestling Minimum Weight
Project (WMWP)
• Wisconsin instituted WMWP in 1989. (Oppliger et al.,
1995)
• Weight loss must be no more than 3 lbs. of
weight loss/week.
• A minimum 7% body fat level was established.
• Testing of athletes along with nutrition
education for coaches was implemented.
• Feedback has been positive from 95% of
coaches.
• Participation has increased.
Wrestling Rules
• The NFSH has developed a national wrestling rule
#1-3-1 that states:
• “An ideal program would be one where a
medical professional would assist in
establishing a minimum weight through the use
of checking body fat and hydration. The
recommended minimum body fat should not be
lower than 7%” (NFHS, 2011)
• Weight cutting can have physiological effects on
performance. (ACSM; Oppliger et al., 1996, updated in 2010)
ACSM Recommendations for
Wrestling
• Education should be provided to coaches and
wrestlers.
• Rubber suits, steam rooms, hot boxes, saunas,
laxatives, and diuretics should not be used for making
weight.
• Weigh-ins immediately prior to competition.
• Daily weigh-ins need to be scheduled before and after
practice.
• The body composition assessed prior to the season.
• Caloric intake needs to support the normal
developmental needs.
Conclusions
(ACSM, 2009; McArdle et al., 2009)
• Athletes do not consume the proper proportions of
nutrients
• CHO amount depends on the athletes daily
expenditure, sport, gender, and conditions
• Protein needs can be met through diet alone
• Athletes eat too much “junk food”
• Athletes in sports that require lean bodies tend to eat
diets with insufficient calories
• Most athletes’ diets are deficient in important minerals,
i.e., calcium, iron, & zinc.
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.
• Subscribe to professional journals that include
nutrition articles.
What Can the Coach Do?
• Locate nutrition experts, including dietitians, university
nutrition faculty, or sports medicine staff.
• Implement peer-led programs like Athletes
Targeting Healthy Exercise & Nutrition Alternatives
(ATHENA). (Eliot et al., 2008)
• Have athletes keep a record of their diet that is
reviewed periodically by a person knowledgeable in
nutrition.
• When working with children, discuss nutritional needs
of the athlete with parents.
General Dietary Guidelines for
Athletes
• Tailored to meet individual needs
• Nutrition should prepare athletes for: practice,
competition and recovery
• Educated to make proper food selection and
informed supplement using interactive
resources
Sports, Cardiovascular, and
Wellness Nutrition practice
group (http://www.scandpg.org)
Precompetition Diets
• Foods eaten just before a contest will contribute
virtually nothing to performance.
• Experts recommend that the typical pregame meal
should be eaten no later than 1 to 4 hours prior to
the contest. (ACSM, 2009)
• Eat low-fat, easy-to-digest foods.
• Liquid meals increase hydration and are less likely
to cause bloating or “heavy” feeling.
• Foods should provide 150 to 300 grams of CHO or
3 to 5 grams/kg of body weight. (McArdle et al., 2009)
Nutrition During Competition
• One hour of highly intense exercise can
reduce liver glycogen by 55% and 2 hours
can almost completely deplete both liver and
muscle glycogen.
• CHO consumption during long-duration
exercise (1 to 3 hours at 70% to 80%
VO2max ) allows muscle cells to rely on
blood glucose for energy.
• Recommended fluid source of CHO is 8 oz. of
a 5% CHO solution consumed every 15-20
min. Especially for morning workouts.
Nutrition After Competition
• Dietary goals are to replace muscle glycogen and
ensure quick recovery.
• A carbohydrate intake of approximately 1.0–
1.5 g/kg body mass (0.5–0.7 g/lb) during the
first 30 min and again every 2 h for 4–6 h will
be adequate to replace glycogen stores.
• Timing of CHO ingestion is important as
glycogen levels will replenish faster if the food
is consumed within 30 minutes – 1 hour.
• Protein consumed after exercise will provide
amino acids for building and repair of muscle
tissue.
Nutrition and Injury Recovery
• Weight gain is a concern with forced inactivity due to
injury.
• Athletes who are ill/injured should not reduce total
caloric intake as metabolism may increase as the
body repairs itself.
• Recommend cross training during recovery.
• Runners can ride stationary bikes or run in swimming
pools.
• Those with infectious illnesses and unable to exercise
should establish a caloric intake based on their BMR
until they are healthy.
Nutrition and Recovery
(Bucci, 1995; Harrison, n.d.)
• CHO stimulates insulin/insulin growth factor which
helps tissue building.
• Proteins (amino acids) contain the building blocks
for connective tissue and muscle.
• Anti-inflammatory foods encouraged: garlic, cocoa,
tea, blueberries, pineapple
• Proteolytic enzymes are known to inactivate
bradykinins, reduce viscosity of extracellular fluid,
and help molecular debridement): cheese, rye,
papaya
• Free fatty acids contain eicosanoids, which can
reduce pain, cause vasodilation and enhance the
immune system
Managing Body Weight
• Body weight consists of water, fat, and lean tissue.
• Muscle is denser than fat.
• In order to maintain weight an athlete’s caloric
intake must equal caloric expenditure.
• Consume too many calories per day the excess
calories are converted to fat. Too few, stored
fat will be metabolized to form energy.
• Severe caloric restrictions (fasting) result in protein
breakdown.
• Athletes should only weigh themselves once/week
at the same time of day and after going to the
bathroom.
Managing Body Weight
• Percentage of body fat = the ratio of fat to lean
body weight
• Better measurement for weight management
and is commonly referred to as body
composition.
• Ranges for most active young females are 14-24%
and active young males are 7-17%.
• Lowest reference body fat for males is 5% and
in females it is 12% (Sammarone Turocy et al., 2011)
• NATA position statement “Safe weight loss and
maintenance practices in sport and exercise”
(Sammarone Turocy et al., 2011) is an excellent resource
Minimal Competitive Weight (MCW)
Percent body fat can be used to accurately
calculate an athlete’s minimal competitive
weight so they can excel during the season.
Sample Equation: [MCW = LBW / % fat desired]
• Determine % fat desired (5%); (1 - % fat
desired = 0.95)
• A 135 lb athlete with 14% body fat has lean
body weight (LBW) = 135 x 0.14 = 18.9 lb fat
• 135 lb – 18.9 (fat weight) = 116.10 lb (LBW)
• MCW = 116.10 / 0.95 = 122 lbs
Supplements and Ergogenic
Aids
• Supplements have become very popular with
athletes of all calibers.
• Marketed to make athletes think they will
improve their personal performance and
reach their goals faster.
• It is important for the consumer to evaluate
the marketing claims, research studies, and
safety issues associated with ergogenic aids.
(Manore, Meyer, and Thompson, 2009)
• Many pose adverse health risks or are illegal
and their use will result in disqualification or
other penalties.
Nutritional Supplements
• NATA released two comprehensive position
stands evaluating dietary supplements (Buell
et al., 2013) and anabolic-androgenic steroids
(Kersey et al., 2012)
• Food first philosophy
• Dietary Supplement Health and Education Act
(DSHEA) of 1994
• Supplements can be divided into two
categories: Legal and Illegal
Nutritional Supplements
•
•
•
•
Stimulants are often the most popular legal
supplements for ergogenic purposes.
Caffeine - Touted to be a safe aid and can provide
a boost of energy for the athlete.
Creatine – Athletes requiring short bursts of
energy, allow longer training time, have adverse
side effects: kidney damage, fluid retention,
muscle cramps, upset stomach, and diarrhea.
Amino acids – some cause muscle building and
repair, excess may stress the urinary system.
Herbals – may produce stimulatory and/or calming
effects but may have adverse interactions with
other drugs.
Anabolic-Androgenic Products
• Illegal supplements include the following but are are
mostly legal products when used in therapeutic
doses under physician or veterinarian's care.
• Anabolic steroids – high doses build muscle but
have many adverse effects
• Erythropoietin (EPO) - stimulates RBC proliferation,
increased viscosity makes the heart work harder
• Amphetamines – stimulants that block fatigue
messages to the brain, associated cardiac problems
• Gammahydroxybutyrate (GHB) – deep sleep aid,
suggested HGH is released in this sleep cycle