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					chapter
  Nutritional Factors in Health and
             Performance
10
           Nutritional Factors
           in Health and
           Performance



           Kristin Reimers, PhD, RD
            Chapter Objectives

• Identify the protein, carbohydrate, and fat recom-
  mendations for athletes.
• Discern between dietary recommendations for
  disease prevention and recommendations for
  performance.
• Identify and apply appropriate hydration practices
  for athletes.
• Apply precompetition and posttraining eating
  strategies and advise athletes on guidelines for
  weight gain and weight loss.
                                           (continued)
   Chapter Objectives (continued)

• Recognize signs and symptoms of eating disorders.
• Understand the importance of having an inter-
  vention and referral system in place for athletes
  suspected of having an eating disorder.
• Recognize the prevalence and etiologies of obesity.
• Assist in the assessment process for obese
  individuals.
             Section Outline

• Role of the Nutritionist
         Role of the Nutritionist

• Responsibilities of the nutritionist include
  the following:
  – Personalized nutritional counseling: weight loss and
    weight 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
              Section Outline

• How to Evaluate the Adequacy of the Diet
  – Standard Nutrition Guidelines
  – Dietary Reference Intakes
           How to Evaluate
       the Adequacy of the Diet

• Standard Nutrition Guidelines
  – Most athletes have two basic dietary goals:
     • Eating to maximize performance
     • Eating for optimal body composition
           How to Evaluate
       the Adequacy of the Diet

• Standard Nutrition Guidelines
  – 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
                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
Figure 10.1
              How to Evaluate
          the Adequacy of the Diet

• Standard Nutrition Guidelines
  – The color bands of MyPyramid represent five food
    groups that are needed each day for health:
     •   Grains
     •   Vegetables
     •   Fruits
     •   Milk
     •   Meat and beans
                  Key Point

• MyPyramid is an excellent starting point
  from which to evaluate the adequacy of an
  athlete’s diet. If a diet provides a variety of
  foods 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.
Table 10.1
           How to Evaluate
       the Adequacy of the Diet
• Dietary Reference Intakes
  – In 2005, the DRIs replaced the ―Recommended
    Dietary 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 the
       estimated average requirement
     • An adequate intake level when a recommended intake
       cannot be based on an estimated average requirement
     • Tolerable upper intake levels above which risk of toxicity
       increases
                 Section Outline

• Macronutrients
  – Protein
     • Structure and Function of Proteins
     • Dietary Protein
     • Protein Requirements
         – General Requirements
         – Increased Requirements for Athletes

                                                 (continued)
     Section Outline (continued)

• Macronutrients
  – Carbohydrates
     •   Structure and Sources of Carbohydrates
     •   Dietary Carbohydrate
     •   Glycemic Index
     •   Fiber
     •   Carbohydrate Requirements
  – Lipids
     •   Structure and Function of Lipids
     •   Fat and Disease
     •   Fat Requirements and Recommendations
     •   Fat and Performance
             Macronutrients

• A macronutrient is a nutrient that is
  required in significant amounts in the diet.
• Three important classes of macronutrients
  are protein, carbohydrates, and lipids.
                Macronutrients

• Protein
  – Structure and Function of Proteins
     • More than half of the amino acids can be synthesized by
       the 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 be
       obtained through the diet.
     • Proteins provide 4 kcal/g.
Table 10.2
                 Macronutrients

• Protein
  – Dietary Protein
     • high-quality (complete) protein: A protein with an amino
       acid 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.
                Macronutrients

• Protein
  – Protein Requirements
     • 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%.
                 Key Point

• Recommendations to increase or decrease
  protein intake should be made on an indi-
  vidual basis after the normal diet has been
  analyzed 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 intake
  of all essential amino acids.
                Macronutrients

• Protein
  – Protein Requirements
     • 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.
               Macronutrients

• Carbohydrates
  – The primary role of carbohydrate in human
    physiology is to serve as an energy source.
  – Carbohydrates provide 4 kcal/g.
                Macronutrients

• Carbohydrates
  – Structure and Sources of Carbohydrates
     • Monosaccharides (glucose, fructose, and galactose) are
       single-sugar molecules.
     • Disaccharides (sucrose, lactose, and maltose) are
       composed of two simple sugar units joined together.
     • Polysaccharides, also known as complex carbohydrates,
       contain up to thousands of glucose units.
                Macronutrients

• Carbohydrates
  – Dietary Carbohydrate
     • All types of dietary carbohydrate—sugars as well as
       starches—are effective in supplying the athlete with
       glucose and glycogen.
     • Consumption of a mix of sugars and starches is desirable.
                 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.
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.
                                                       Table 10.3




Adapted, by permission, from Foster-Powell, Holt, and Brand-Miller, 2002.
                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 levels
       by consuming maximal levels of carbohydrate, approxi-
       mately 8 to 10 g/kg of body weight.
                Key Point

• Some aerobic endurance athletes have
  maximal carbohydrate requirements, up to
  10 g/kg per day. Most athletes do not
  deplete muscle glycogen on a daily basis,
  however, and therefore have lower carbo-
  hydrate requirements.
                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.
                 Macronutrients

• Lipids
  – Fat and Disease
     • High levels of cholesterol or unfavorable ratios of
       lipoproteins 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.
Table 10.4
                 Macronutrients

• Lipids
  – Fat Requirements and Recommendations
     • The recommendation for the general public from health
       organizations 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)
                 Macronutrients

• Lipids
  – Fat Requirements and Recommendations
    (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 fat
       provide 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.
                 Key Point

• Fat phobia, or fear of eating fat, can lead
  to nutrient deficiencies, which harm
  performance. Athletes who eat very little
  or no fat should receive nutritional coun-
  seling and information.
                 Macronutrients

• When Should Athletes Decrease Dietary
  Fat?
  – Need to increase carbohydrate intake to support
    training 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.
                 Macronutrients

• When Should Athletes Decrease Dietary
  Fat?
  – Need to reduce total caloric intake to achieve weight
    loss
     • 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.
                 Macronutrients

• Lipids
  – Fat and Performance
     • Intramuscular fatty acids are more important during activity.
     • Circulating fatty acids (from adipose tissue or diet) are more
       important during recovery.
     • Consumption of high-fat diets may enhance performance
       and result in longer distance to exhaustion.
     • The effects of high-fat diets vary, depending on the
       individual.
                 Section Outline

• Micronutrients
  – Vitamins
  – Minerals
     • Iron
     • Calcium
              Micronutrients

• A micronutrient is a nutrient that is required
  in small amounts (typically measured in
  milligram—or even smaller—quantities) in
  the diet.
• Two primary types of micronutrients are
  vitamins and minerals.
              Micronutrients

• Vitamins
  – Vitamins are organic substances (i.e., containing
    carbon atoms) that cannot be synthesized by the
    body.
  – They are needed in very small amounts and perform
    specific metabolic functions.
Table 10.5




             (continued)
             (continued)

Table 10.5 (continued)
                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.
Table 10.6




             (continued)
Table 10.6 (continued)
             (continued)
                 Micronutrients

• Minerals
  – Iron
     • Iron is a constituent of hemoglobin and myoglobin and,
       as such, plays a role in oxygen transport and utilization
       of energy.
                 Micronutrients

• Minerals
  – Calcium
     • Athletes who consume low-calcium diets may be at risk for
       osteopenia and osteoporosis (deterioration of bone tissue
       leading to increased bone fragility and risk of fracture).
                 Section Outline

• Fluid and Electrolytes
  – Water
     • Fluid Balance
     • Risks of Dehydration
     • Monitoring Hydration Status
  – Electrolytes
  – Fluid Replacement
     • Before Activity
     • During Activity
     • After Activity
          Fluid and Electrolytes

• Water
  – Water is the largest component of the body,
    representing from 45% to 70% of a person’s body
    weight.
  – Total body water is determined largely by body
    composition; muscle tissue is approximately 75%
    water, whereas fat tissue is about 20% water.
          Fluid and Electrolytes

• Water
  – Fluid Balance
     • The average fluid requirement for adults is estimated to be
       2 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.
          Fluid and Electrolytes

• Water
  – Risks of Dehydration
     • Fluid loss equal to as little as 1% of total body weight can
       be 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.
                Key Point

• Consuming adequate fluids before, during,
  and after training and competition is
  essential to optimal resistance training
  and aerobic endurance exercise.
              Fluid and Electrolytes

• Water
  – Monitoring Hydration Status
     • Each pound (0.45 kg) lost during practice represents
       1 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
          Fluid and Electrolytes

• 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, and
    rehydrate before the next training session.
          Fluid and Electrolytes

• Fluid Replacement Guidelines
  – Before a Training Session
     • Encourage athletes to hydrate properly before prolonged
       exercise in a hot environment.
     • Intake should be approximately 16 fluid ounces (0.5 L) of a
       cool beverage 2 hours before a workout.
          Fluid and Electrolytes

• Fluid Replacement Guidelines
  – During a Training Session
     • Provide cool beverages (about 50-70 °F [10-21 °C]).
     • Have fluids readily available, since the thirst mechanism
       does not function adequately when large volumes of water
       are lost.
     • Athletes need to be reminded to drink.
     • Athletes should drink fluid frequently—for example,
       6 to 8 fluid ounces (177-237 ml) every 15 minutes.
          Fluid and Electrolytes

• 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 the
       duration and intensity of exercise, environmental
       temperature, and the athlete.
                  Section Outline

• Precompetition and Postexercise Nutrition
  – Precompetition Food Consumption
     •   Purpose
     •   Timing
     •   Practical Considerations
     •   Carbohydrate Loading
  – Postexercise Food Consumption
           Precompetition and
          Postexercise Nutrition

• Precompetition Food Consumption
  – Purpose
     • The primary purpose is to provide fluid and energy for the
       athlete 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.
           Precompetition and
          Postexercise Nutrition

• Precompetition Food Consumption
  – Practical Considerations
     • It is important for athletes to consume food and beverages
       that they like, that they tolerate well, that they are used to
       consuming, and that they believe result in a winning
       performance.
                 Key Point

• The primary goal of the precompetition meal
  is to provide fluid and energy for the athlete
  during performance.
          Precompetition and
         Postexercise Nutrition

• Precompetition Food Consumption
  – Carbohydrate Loading
     • Carbohydrate loading is a technique used to enhance
       muscle glycogen prior to long-term aerobic endurance
       exercise.
          Precompetition and
         Postexercise Nutrition

• 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.
                Section Outline

• Weight and Body Composition
  – Energy Requirements
     • Factors Influencing Energy Requirements
     • Estimating Energy Requirements
  – Weight Gain
  – Weight Loss
  – Rapid Weight Loss
   Weight and Body Composition

• 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 °C (or 2.2
    pounds of water 1.8 °F).
  – Energy (caloric) requirement is defined as energy
    intake equal to expenditure, resulting in constant
    body weight.
   Weight and Body Composition

• Energy Requirements
  – Factors Influencing Energy Requirements
     • Resting metabolic rate
     • Thermic effect of food
     • Physical activity
                 Key Point

• There is a wide range of energy expendi-
  tures and energy intakes among sports due
  to differences in body mass, intensity of
  training, work efficiency, and the size of the
  involved muscle mass.
   Weight and Body Composition

• Energy Requirements
  – Estimating Energy Requirements
     • Energy needs can be loosely estimated using the
       guidelines found in table 10.7.
     • Athletes can also use food diaries during periods of stable
       body weight to estimate requirements.
Table 10.7
   Weight and Body Composition

• Weight Gain
  – If all the extra calories consumed are used for
    muscle growth during resistance training, then
    about 2,500 extra kilocalories are required for
    each 1-pound (0.45 kg) increase in lean tissue.
                Key Point

• Gains in body mass and strength occur
  when the athlete consumes adequate
  calories and dietary protein and engages in
  a progressive resistance training program.
   Weight and Body Composition

• Weight Loss
  – If all the expended or dietary-restricted kilocalories
    apply to body fat loss, then a deficit of 3,500 kcal will
    result 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.
                 Key Point

• The most important goal for weight loss is
  to achieve a negative calorie balance.
  Therefore, the types of foods the individual
  consumes are less important than the
  portions of those foods. The focus is on
  calories.
   Weight and Body Composition

• Rapid Weight Loss
  – For athletes who desire to minimize lean tissue loss,
    small decreases in caloric intake to achieve gradual
    weight loss are indicated.
                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
Eating Disorders: Anorexia Nervosa
       and 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.
                                            Figure 10.2




Reprinted, by permission, from American Psychiatric Association, 1994.
                                            Figure 10.3




Reprinted, by permission, from American Psychiatric Association, 1994.
Eating Disorders: Anorexia Nervosa
       and Bulimia Nervosa

• Definitions and Criteria
  – Warning Signs for Anorexia Nervosa
     • Commenting repeatedly about being or feeling fat
     • Asking questions such as ―Do you think I’m 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
Eating Disorders: Anorexia Nervosa
       and Bulimia Nervosa

• Definitions and Criteria
  – 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
Eating Disorders: Anorexia Nervosa
       and Bulimia Nervosa

• Definitions and Criteria
  – 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 one’s body
     •   Strong denial that a problem exists even when there is
         hard evidence
Eating Disorders: Anorexia Nervosa
       and Bulimia Nervosa

• Management and Care
  – Steps in the Management of Eating Disorders
     •   Fact finding
     •   Confronting
     •   Referring
     •   Following up
Eating Disorders: Anorexia Nervosa
       and Bulimia Nervosa

• Management and Care
  – What Not to Do
     • The strength and conditioning professional’s job is not to
       treat an eating disorder; it is to be aware of warning signs
       and to refer when a problem is suspected.
            Section Outline

• Obesity
Table 10.8
                Key Point

• Obesity is not the same condition in each
  individual. Thorough assessment helps
  determine which treatment is appropriate
  and, more important, whether the individual
  is ready for treatment.

				
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