27729930 Nutritional Factors in Health and Performance[1]

8/8/2019 27729930 Nutritional Factors in Health and Performance[1]

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Chapter Objectives

Identify the protein, carbohydrate, and fat recom-mendations for athletes.

Discern between dietary recommendations fordisease prevention and recommendations forperformance.

Identify and apply appropriate hydration practicesfor athletes.

Apply precompetition and posttraining eatingstrategies and advise athletes on guidelines forweight gain and weight loss.

(continued)


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Nutritionists

Dietary advice based on Food Guide Pyramid and

Dietary Reference Intakes

Some states regulate nutritional program orsupplement recommendations

Recognise that athletes have physiological needs

that are quite different from a sedentary individual

No one size fits all program Needs based on age, body size, sex, genetics,

environmental training conditions and exercise

prescription


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Section Outline

Role of the Nutritionist

Responsible for the athletes dietary needs

and works as a member of the teamdedicated to improving the athletes

performance


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Role of the Nutritionist

Responsibilities of the nutritionist include

the following:

Personalized nutritional counseling: weight loss andweight gain, strategies to improve performance,

menu planning, dietary supplements

Dietary analysis of food records

Nutritional education: presentations and handouts Referral and treatment of eating disorders


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Section Outline

How to Evaluate the Adequacy of the Diet

Standard Nutrition Guidelines

Dietary Reference Intakes


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How to Evaluate

the Adequacy of the Diet


Most athletes have two basic dietary goals:

Eating to maximize performance Eating for optimal body composition


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How to Evaluate



Food Guide Pyramid

Used to evaluate appropriate calorie level Used to evaluate appropriate nutrient levels to prevent

nutrient deficiency or toxicity

Developed by the U.S. Department of Agriculture in 1992

Updated to MyPyramid in 2005

Suggested servings based on 2000 calorie/day diet


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MyPyramid

Figure 10.1 (next slide)

Displays recommended types and amounts of food

to eat daily For more information and resources, go to

www.mypyramid.gov


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Figure 10.1


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How to Evaluate



The color bands of MyPyramid represent five food

groups that are needed each day for health: Grains

Vegetables

Fruits

Milk

Meat and beans

(the yellow band between fruits and milk represents

Oilsnot a food group, but provide EFAs and

Vitamin E)


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Key Point

MyPyramid is an excellent starting point

from which to evaluate the adequacy of an

athletes diet. If a diet provides a variety offoods from each group, it is likely adequate

for vitamins and minerals. However, if the

diet excludes an entire food group, specific

nutrients may be lacking.


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Section Outline

Weight and Body Composition

Energy Requirements

Factors Influencing Energy Requirements Estimating Energy Requirements

Weight Gain

Weight Loss

Rapid Weight Loss


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Energy Requirements

Energy is commonly measured in kilocalories (kcal

or calories). A kilocalorie is the work or energy required to raise

the temperature of 1 kg of water 1 rC (or 2.2 pounds

of water 1.8 rF).

Energy (caloric) requirement is defined as energyintake equal to expenditure, resulting in constant

body weight.


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Energy Requirements

Factors Influencing Energy Requirements

Resting metabolic rate Thermic effect of food

Physical activity


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Key Point

There is a wide range of energy expendi-

tures and energy intakes among sports due

to differences in body mass, intensity oftraining, work efficiency, and the size of the

involved muscle mass.


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Energy Requirements

Estimating Energy Requirements

Energy needs can be loosely estimated using theguidelines found in table 10.7.

Athletes can also use food diaries during periods of stable

body weight to estimate requirements.

Quick calculation for baseline is BW x 11


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Weight Gain

If all the extra calories consumed are used for

muscle growth during resistance training, thenabout 2,500 extra kilocalories are required for

each 1-pound (0.45 kg) increase in lean tissue.


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Key Point

Gains in body mass and strength occur

when the athlete consumes adequate

calories and dietary protein and engages ina progressive resistance training program.


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Weight Loss

If all the expended or dietary-restricted kilocalories

apply to body fat loss, then a deficit of 3,500 kcal willresult in a 1-pound (0.45 kg) fat loss.

The maximal rate of fat loss appears to be approx-

imately 1% of body mass per week.

This is an average of 1.1 to 2.2 pounds (0.5-1.0 kg)per week and represents a daily caloric deficit of

approximately 500 to 1,000 kcal.


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Key Point

The most important goal for weight loss is

to achieve a negative calorie balance.

Therefore, the types of foods the individualconsumes are less important than the

portions of those foods. The focus is on

calories.


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Rapid Weight Loss

For athletes who desire to minimize lean tissue loss,

small decreases in caloric intake to achieve gradualweight loss are indicated.


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Table 10.1


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Task 1

Calculate typically how many calories your

partner ingested per day.

Find out what calorie category they fall into

and how much of food they have to intake


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Table 10.7


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Task 2

Find out what category of activity level your

partner falls into.

Work out their weight in KG

Find how much kcal they should beconsuming


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How to Evaluate

the Adequacy of the Diet Dietary Reference Intakes

In 2005, the DRIs replaced the RecommendedDietary Allowances.

The DRI for each nutrient includes the following: Estimated average requirement and its standard deviation

by age and gender

Recommended dietary consumption based on theestimated average requirement

An adequate intake level when a recommended intakecannot be based on an estimated average requirement

Tolerable upper intake levels above which risk of toxicityincreases


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Section Outline

Macronutrients Protein

Structure and Function of Proteins

Dietary Protein

Protein Requirements

General Requirements

Increased Requirements for Athletes

(continued)


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Section Outline (continued)

Macronutrients Carbohydrates

Structure and Sources ofCarbohydrates

Dietary Carbohydrate

Glycemic Index

Fiber

Carbohydrate Requirements

Lipids Structure and Function of Lipids Fat and Disease

Fat Requirements and Recommendations

Fat and Performance


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Macronutrients

A macronutrient is a nutrient that is

required in significant amounts in the diet.

Three important classes of macronutrientsare protein, carbohydrates, and lipids.


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Macronutrients

Protein

Structure and Function of Proteins

More than half of the amino acids can be synthesized bythe human body and are commonly called nonessential

amino acids because they do not need to be consumed in

the diet.

Nine of the amino acids are essential because the body

cannot manufacture them and therefore they must beobtained through the diet.

Proteins provide 4 kcal/g.

Goal for athletes is to maintain positive nitrogen balance


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Table 10.2


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Macronutrients

Protein

Dietary Protein

high-quality (complete) protein: A protein with an aminoacid pattern similar to that needed by the body. Usually of

animal origin.

low-quality (incomplete) protein: A protein that is deficient in

one or more of the essential amino acids. Usually of plant

origin.

Can combine beans and rice, corn and beans, corn tortillas

and refried beans, peanut butter and bread

Does not have to be combined at the same meal


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Macronutrients

Protein


General Requirements Assuming that caloric intake is adequate and that two-thirds

or more of the protein is from animal sources, the recom-

mended intake for protein for adults is 0.8 g/kg (0.36 g/pound)

of body weight for both men and women.

Expressed as a percent of daily caloric intake, a common

protein intake recommendation is 10% to 15%.


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Key Point

Recommendations to increase or decrease

protein intake should be made on an indi-

vidual basis after the normal diet has beenanalyzed and caloric intake considered. A

mixed diet is the best source of high-quality

protein. Strict vegetarians must plan their

diet carefully to ensure an adequate intakeof all essential amino acids.


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Macronutrients

Protein


Increased Requirements for Athletes Based on current research, it appears that the protein

requirements for athletes are between 1.5 and 2.0 g/kg

of body weight, assuming that caloric intake and protein

quality are adequate. This is double (or more) than the

0.8 g/kg for the general population


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Macronutrients

Carbohydrates

The primary role of carbohydrate in human

physiology is to serve as an energy source. Carbohydrates provide 4 kcal/g.

Chemical structure carbon, hydrogen, and oxygen

(so is fat and protein, but protein also contains

nitrogen) 5-6 g/kg/day for athletes; 8-10 g/kg for aerobic

athletes (>90 min/day)


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Macronutrients

Carbohydrates

Structure and Sources ofCarbohydrates

Monosaccharides (glucose, fructose, and galactose) aresingle-sugar molecules.

Disaccharides (sucrose-(table sugar), lactose, and maltose

(glucose + glucosein alcohol)) are composed of two

simple sugar units joined together.

Polysaccharides, also known as complex carbohydrates,contain up to thousands of glucose units. Starch, fiber, and

glycogen


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Macronutrients

Carbohydrates

Dietary Carbohydrate

All types of dietary carbohydratesugars as well asstarchesare effective in supplying the athlete with

glucose and glycogen.

Consumption of a mix of sugars and starches is desirable.


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Macronutrients

Carbohydrates

Glycemic Index

The GI classifies a food by how high and for how long it raises

blood glucose.

The reference food is glucose or white bread (GI = 100).

Foods that are digested quickly and raise blood glucose (and

insulin) rapidly have a high GI.

Foods that take longer to digest and thus slowly increase blood

glucose (and therefore stimulate less insulin) have a low GI. Limited use due to cooking, processing, eating the food as part of

a meal, eating a different amount, and eating at a different time of

day (and even what was eaten the day before)


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Glycemic Index (GI) of Various Foods

Table 10.3 (next slide)

The table uses white bread (GI = 100) as a

standard. When variations exist in a food item, the mean is

reported.


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Table 10.3

Adapted, by permission, from Foster-Powell, Holt, and Brand-Miller, 2002.


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Macronutrients

Carbohydrates Fiber

The DRI for fiber is 38 and 25 g/day for young men and

women, respectively. This level of fiber may be excessive for some aerobic

endurance athletes.

Carbohydrate Requirements The general recommendation is to consume 50% to 55%

of total daily calories as carbohydrate.

Aerobic endurance athletes who train for long durations(90 minutes or more daily) should replenish glycogen levelsby consuming maximal levels of carbohydrate, approxi-mately 8 to 10 g/kg of body weight.


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Key Point

Some aerobic endurance athletes have

maximal carbohydrate requirements, up to

10 g/kg per day. Most athletes do notdeplete muscle glycogen on a daily basis,

however, and therefore have lower carbo-

hydrate requirements.


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Macronutrients

Lipids

Structure and Function of Lipids

Fatty acids containing no double bonds are saturated. Fatty acids containing one double bond are mono-

unsaturated.

Fatty acids containing two or more double bonds are

polyunsaturated.

Fats provide approximately 9 kcal/g.


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Macronutrients

Lipids

Fat and Disease

High levels of cholesterol or unfavorable ratios oflipoproteins are associated with increased risk of heart

disease.

High levels of HDLs protect against heart disease.

HDLs can be increased by exercise and weight loss.


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Table 10.4


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Macronutrients

Lipids


The recommendation for the general public from healthorganizations such as the American Heart Association is

that fat should constitute 30% or less of the total calories

consumed.

It is recommended that 20% of the total calories (or two-

thirds of the total fat intake) come from monounsaturated or

polyunsaturated sources and 10% from saturated fats (one-

third of total fat intake).

(continued)


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Macronutrients

Lipids


(continued) The Sub-Committee on Nutrition of the United Nations

recommends an upper limit for fat intake of 35% of total

calories for active people.

The American Heart Association and the Sub-Committee

on Nutrition of the United Nations recommend that fatprovide at least 15% of the total calories in the diets of

adults and at least 20% of total calories in the diets of

women of reproductive age.


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Key Point

Fat phobia, or fear of eating fat, can lead

to nutrient deficiencies, which harm

performance. Athletes who eat very littleor no fat should receive nutritional coun-

seling and information.

Fat phobia caused by nations focus on

overconsumption of fatunfounded formost athletes as very few performance

enhancements from significantly fat intake


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Macronutrients

When Should Athletes Decrease Dietary

Fat?

Need to increase carbohydrate intake to supporttraining type

In this case, to ensure adequate protein provision, fat is the

nutrient of choice to decrease so that that caloric intake can

remain similar while carbohydrate is increased.


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Macronutrients

When Should Athletes Decrease Dietary

Fat?

Need to reduce total caloric intake to achieve weightloss

Because fat is dense in calories and is highly palatable,

decreasing dietary fat, if the diet has excess fat, can help

reduce caloric intake.

Need to decrease elevated blood cholesterol Some young athletes are strongly predisposed to heart

disease, although this is uncommon.


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Macronutrients

Lipids Fat and Performance

Intramuscular fatty acids are more important during activity.

Circulating fatty acids (from adipose tissue or diet) are moreimportant during recovery.

Consumption of high-fat diets may enhance performanceand result in longer distance to exhaustion.

The effects of high-fat diets vary, depending on the

individual. Elite athletes may need >30% fat intake and aerobic

athletes may approach 50%

Lower limit of


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Section Outline

Micronutrients

Vitamins

Minerals Iron

Calcium


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Micronutrients

A micronutrient is a nutrient that is required

in small amounts (typically measured in

milligramor even smallerquantities) inthe diet.

Two primary types of micronutrients are

vitamins and minerals.


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Micronutrients

Vitamins

Vitamins are organic substances (i.e., containing

carbon atoms) that cannot be synthesized by thebody.

They are needed in very small amounts and perform

specific metabolic functions. Vitamins supplements

are catalysts and work only in the presence of well-

timed eating


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Table 10.5

(continued)


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Table 10.5 (continued)(continued)


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Micronutrients

Minerals

Minerals are required for a wide variety of metabolic

functions. For athletes, minerals are important for bone health,

oxygen-carrying capacity, and fluid and electrolyte

balance.


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Table 10.6

(continued)


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Table 10.6 (continued)(continued)


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Micronutrients

Minerals

Iron

Iron is a constituent of hemoglobin and myoglobin and,as such, plays a role in oxygen transport and utilization

of energy.


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Micronutrients

Minerals

Calcium

Athletes who consume low-calcium diets may be at risk forosteopenia and osteoporosis (deterioration of bone tissue

leading to increased bone fragility and risk of fracture).


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Fluid and Electrolytes

Water

Water is the largest component of the body,

representing from 45% to 70% of a persons bodyweight.

Total body water is determined largely by body

composition; muscle tissue is approximately 75%

water, whereas fat tissue is about 20% water.

Most forgotten/overlooked nutrient in nutritional

planning


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Water

Fluid Balance

The average fluid requirement for adults is estimated to be2 to 2.7 quarts (1.9-2.6 L) per day.

Athletes sweating profusely for several hours per day may

need to consume an extra 3 to 4 gallons (11-15 L) of fluid

to replace losses.


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Water

Risks of Dehydration

Fluid loss equal to as little as 1% of total body weight canbe associated with an elevation in core temperature during

exercise.

Fluid loss of 3% to 5% of body weight results in cardio-

vascular strain and impaired ability to dissipate heat.

At 7% loss, collapse is likely.


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Key Point

Consuming adequate fluids before, during,

and after training and competition is

essential to optimal resistance trainingand aerobic endurance exercise.


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Water

Monitoring Hydration Status

Each pound (0.45 kg) lost during practice represents1 pint (0.5 L) of fluid loss.

Signs of dehydration include the following:

Dark yellow, strong-smelling urine

Decreased frequency of urination

Rapid resting heart rate

Prolonged muscle soreness


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Electrolytes The major electrolytes lost in sweat are sodium

chloride, and, to a lesser extent, potassium.

Fluid Replacement The ultimate goal is to start exercise in a hydrated

state, avoid dehydration during exercise, andrehydrate before the next training session.

May need to make it taste good for those notaccustomed to drinking water

A word on caffeinated beverages: urine productionif not accustomed to it, urine production if used to it


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Fluid Replacement Guidelines

Before a Training Session

Encourage athletes to hydrate properly before prolongedexercise in a hot environment.

Intake should be approximately 16 fluid ounces (0.5 L) of a

cool beverage 2 hours before a workout.


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Fluid Replacement Guidelines During a Training Session

Provide cool beverages (about 50-70 rF [10-21 rC]).

Have fluids readily available, since the thirst mechanismdoes not function adequately when large volumes of waterare lost.

Athletes need to be reminded to drink.

Athletes should drink fluid frequentlyfor example,

6 to 8 fluid ounces (177-237 ml) every 15 minutes. Chugging is good!

If exercising > 1 hr, 6-8% CHO sport drink absorbed morerapidly; water best if < 1 hr.


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Fluid Replacement Guidelines

After a Training Session

Athletes should replenish fluids with at least 1 pint (0.5 L)of fluid for every pound (0.45 kg) of body weight lost.

Weight should be regained before the next workout.

Water is an ideal fluid replacement, although flavored

beverages may be more effective at promoting drinking.

The ideal fluid replacement beverage depends on theduration and intensity of exercise, environmental

temperature, and the athlete.


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Section Outline

Precompetition and Postexercise Nutrition

Precompetition Food Consumption

Purpose Timing

Practical Considerations

Carbohydrate Loading

Postexercise Food Consumption


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Precompetition andPostexercise Nutrition


Purpose

The primary purpose is to provide fluid and energy for theathlete during the performance.

Timing

The most common recommendation is to eat 3 to 4 hours

prior to the event to avoid becoming nauseated or uncom-

fortable during competition. Overall nutritional plan at least as important than the pre-

game meal


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Practical Considerations

It is important for athletes to consume food and beveragesthat they like, that they tolerate well, that they are used to

consuming, and that they believe result in a winning

performance.


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Key Point

The primary goal of the precompetition meal

is to provide fluid and energy for the athlete

during performance.


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Carbohydrate Loading

Carbohydrate loading is a technique used to enhance

muscle glycogen prior to long-term aerobic endurance

exercise (may also benefit high intensity, short duration

performance).

Three days high CHO diet (8-10 g/kg/day) with tapering

exercise the week before competition and complete rest the

day before the event. Muscle glycogen stores 20-40%above normal


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Postexercise Food Consumption

Data suggest that high-GI foods consumed after

exercise replenish glycogen faster than low-GI

foods.

Although emphasis is usually placed on carbo-

hydrate, in practical terms, consuming a balanced

meal ensures the availability of all substrates for

adequate recovery, including amino acids.


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Pre- and Post-WorkoutMealnot in book

Much research now being done on

maximizing S&C workouts

Pre-workout 6 g PRO (BCAA) with 32 g CHO Post-workout 30 g PRO (whey) with 30-100 g

CHO


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Section Outline

Eating Disorders: Anorexia Nervosa

and Bulimia Nervosa

Definitions and Criteria Management and Care

Steps in the Management of Eating Disorders

What Not to Do


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Eating Disorders: Anorexia Nervosaand Bulimia Nervosa

Definitions and Criteria

Anorexia nervosa is self-imposed starvation in an

effort to lose weight and achieve thinness.

Bulimia nervosa is characterized by recurrent

consumption of food in amounts significantly greater

than would customarily be consumed at one sitting.


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Figure 10.2

Reprinted, by permission, from American Psychiatric Association, 1994.


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Figure 10.3

Reprinted, by permission, from American Psychiatric Association, 1994.


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Warning Signs for Anorexia Nervosa

Commenting repeatedly about being or feeling fat

Asking questions such as Do you think Im fat? when

weight is below average

Dramatic weight loss for no medical reason

Reaching a weight that is below the ideal competitive

weight Continuing to lose weight even during the off-season

Preoccupation with food, calories, and weight


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Warning Signs for Bulimia

Eating secretively

Disappearing repeatedly immediately after eating

Appearing nervous if something prevents the person from

being alone after eating

Losing or gaining extreme amounts of weight

Smell or remnants of vomit in the rest room or elsewhere Disappearance of large amounts of food


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Warning Signs for Both Disorders

Complaining frequently of constipation or stomachaches

Mood swings

Social withdrawal

Relentless, excessive exercise

Excessive concern about weight

Strict dieting followed by binges Increasing criticism of ones body

Strong denial that a problem exists even when there is

hard evidence


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Management and Care

Steps in the Management of Eating Disorders

Fact finding

Confronting

Referring

Following up


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Management and Care

What Not to Do

The strength and conditioning professionals job is not to

treat an eating disorder; it is to be aware of warning signs

and to refer when a problem is suspected.


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Section Outline

Obesity


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Table 10.8


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Key Point

Obesity is not the same condition in each

individual. Thorough assessment helps

determine which treatment is appropriateand, more important, whether the individual

is ready for treatment.

27729930 Nutritional Factors in Health and Performance[1]

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