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Nutritional Considerations. Introduction… . Research shows that, regardless of the sport, an athlete’s diet plays a critical, if not essential, role in performance. Yet misinformation and misconceptions persist among coaches and athletes regarding what constitutes an adequate diet.

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  • Research shows that, regardless of the sport, an athlete’s diet plays a critical, if not essential, role in performance.
  • Yet misinformation and misconceptions persist among coaches and athletes regarding what constitutes an adequate diet.
  • We will first examine available evidence concerning the dietary knowledge and practices of coaches and athletes.
  • Then we will examine dietary recommendations for healthy eating, including the roles of carbohydrates, proteins, fats, vitamins and minerals.
  • Next, we will look at evidence pertaining to protein supplementation and other ergogenic aids.
  • Special attention will be given to the sport of wrestling, which has been plagued with the problem of athletes attempting to lose body weight rapidly by dehydration, and a simple method is provided to assess an athlete’s ability to rehydrate adequately.
  • We will discuss the relationship between nutrition and recovery from injury.
  • Finally, we will use our 3 day calorie tracker to incorporate into our fitness program in the computer lab
a brief history of sports nutrition
A brief history of sports nutrition…
  • Specific text on the diet of ancient athletes are rare.
  • Human muscle energy metabolism began to be studied in the late 19th century

Milo of Croton – 6th century BC

    • Was the first Olympian
    • Would consume 20 pounds of bread and meat a day
      • = 16,000 calories/day
  • Nathan Zuntz – 1911
    • Was a psychologist who discovered you need to combine carbohydrates and fat together to help increase energy

Boston Marathon Studies – 1923

    • A group of scientist we called in to test marathon runners after their race.
    • Their conclusions found that the majority of marathon runners had low blood sugar levels after the race.
      • Low blood sugar levels = hypoglycemia
    • In the next Boston Marathon, a few runners were encouraged to consume high-carbohydrate food.
    • Conclusion = consuming high carbohydrate prevented lower glucose level and improved running time to complete the race

Harvard Dog Studies – 1932

    • Scientist took 2 sled dogs
    • Increased the sled dogs food for 4 hours, 6 hours, 17 hours, 23 hours
    • Provided more carbohydrates after the rest period

Dr. Robert Cade – 1965

    • An ephrologist (kidney specialist) who studied physiology of exercise
    • Came to University of Florida College of Medicine
    • Put together a team who began to work on answering the famous question asked about the football team
      • “Why don’t football players urinate after a game?” 
      • At the time, basic exercise wisdom  discouraged athletes from replenishing liquids lost due to sweating during the game
      • The team lost so much fluid, that they had none left to form urine
    • Dr. Robert Cade began to develop a hydration drink (combined with sugar and salt) that could be absorbed more quickly.
    • Thus, this became the basis of Gatorade

He first used Gatorade on guinea pigs(who were the JV squad)

  • Noticed that in the scrimmage during practice the Varsity would over power the JV team
  • After consuming the Gatorade beverage, in the second half, JV overpowered V
  • Proper nutritional knowledge is imperative for all individuals, but especially for those involved in athletic competitions (Jacobson, Sobonya, & Ransone, 2001).
  • An athlete’s diet has a direct impact on performance, recovery from training and competition, resistance to environmental extremes, recovery from injury, and, to some extent, likelihood of injury.
  • In essence, diet influences virtually all aspects of sports participation.

Most athletes (68%) were familiar with the food groups and 71% reported incorporating them into their diet, but Parr et al. (1984) also demonstrated that athletes largely relied on parents for information about nutrition – followed by TV commercials and magazines.

  • Although the knowledge of most parents concerning nutrition cannot be measured, it is probably safe to assume that both parents and the media represent, at best, marginal sources of current nutritional advice always or often during their college carriers.
nutrients an overview
Nutrients: An Overview
  • According to the American Dietetic Association (2009), eating correctly for sports performance will
    • Help the athlete train longer and at a higher intensity
    • Delay the onset of fatigue
    • Promote recovery
    • Help the athlete’s 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 stomachaches

Although a comprehensive investigation of both macronutrients (required in large amounts) and micronutrients (required in small, or trace, amounts) is beyond the scope of this text, a brief review of the six classes of nutrients is presented.

  • Carbohydrates, fats, and proteins are the macronutrients, and each is important in the diet.
  • The mix of these may change based on fitness levels, exercise goals, and personal food preferences.
  • Vitamins and minerals are micronutrients that contribute to metabolic reactions and tissue structure.
  • And finally, water is essential for substrate transport, waste removal, and joint health (McArdle, Katch & Katch, 2009).
  • Carbohydrates (CHO) are molecules that, by way of their metabolic breakdown, provide energy for high-intensity exercise.
  • The specific forms of CHO used within the body are glucose and glycogen (the storage form of glucose) found in the blood, liver, and skeletal muscle.
  • Carbohydrates consist of carbon, hydrogen, and oxygen atoms, with the number of carbon atoms ranging from three to seven.
  • They fall into three general categories, based on the complexity of the molecule.
  • the simplest forms of CHO are the monosaccharides (a single molecule), which include sugars such as fructose, glucose (blood sugar), and galactose.
  • The next group is the disaccharides (two monosaccharide molecules combined), which include commonly known sugars such as lactose (milk sugar), sucrose (the most common form of sugar in the diet), and maltose.
  • The complex carbohydrates are known as polysaccharides (10 to thousands of monosaccharides linked together) and include compounds such as glycogen, starch, and cellulose (dietary fiber).
  • The majority of dietary CHO is derived from plant sources, primarily grains, seeds, fruits, and vegetables.
  • In a practical context, carbohydrates are classified as either simple (monosaccharides) or complex.
  • In general, complex CHO contain more nutrients and fiber than simple CHO do.
  • The most common form of dietary CHO intake is from simple sugars, primarily foods high in sucrose
    • Soft drinks, candies, and cereals (high in sugar).
  • Although high in caloric content, these foods stimulate insulin release , cause fluctuations in blood glucose levels, and provide little in any way of other nutrients; therefore, they are often referred to as “empty calorie” foods.
  • A superior form of dietary CHO is derived form eating more complex CHO or whole-grain cereals and breads, vegetables, and fruits.
  • The CHO in these foods is in the form of starch found in the cereals and breads or cellulose found in leaves, stems, roots, seeds, and coverings of plants.
  • An added benefit of consuming complex CHO is that they typically contain dietary fiber (indigestible CHO), which may lower cholesterol absorption and is also beneficial to the digestive tract.
  • Daily fiber intake should be between 21 g and 38 g depending on gender and age (McArdle et al., 2009).
  • Another excellent source of CHO is fruits, which can provide a significant amount of CHO in the form of fructose.
  • Fructose, a monosaccharide, is much sweeter than surcose; however, the benefit of fructose is that it “does not stimulate pancreatic insulin secretion” and, as a result, “helps to stabilize blood-glucose and insulin levels” (McArdle et al., 2009).
  • An added benefit of whole-grain breads, cereals, fruits, and vegetables is that they typically contain a wide variety of other nutrients and, as such, help to provide a balanced diet.
  • Although the classifications of simple and complex CHO often are suitable to describe foods containing CHO, these classifications do not represent the way both simple and complex CHO are hydrolyzed and absorbed by the body (Manore, Meyer, & Thompson, 2009)
  • Foods are now also classified as producing either high, moderate, or low glycemic responses.
  • Foods classified as having a high glycemic response typically result in a large and rapid rise in blood glucose and insulin, followed by a rapid decrease in blood glucose.
  • Those foods with a lower glycemic response cause a steadier rise and decline in blood glucose and insulin.
  • Low glycemic index CHO improve diabetes management, reduce the risk of heart disease, reduce hunger and keep a person fuller for longer, and prolong physical endurance, whereas high glycemic CHO help refuel carbohydrate stores after exercise.
carbohydrate muscle
Carbohydrate & Muscle
  • Muscles require CHO as a fuel source during exercise.
  • The recommended percentage proportion of CHO in the diet should range between 60% and 70% of the total calories consumed daily, depending on the exercise frequency and intensity.
  • Regardless of the type of CHO consumed, they all provide approximately 4 kal/g CHO.
  • The average person stores approximately 1500 to 2000 kcal of CHO, the majority of which is in the form of muscle and liver glycogen, with a small portion available and blood glucose (McArdle et al., 2009).
  • All individuals need to consume carbohydrates to maintain body functions or support exercise; however, athlete engaging in different activities need to consume carbohydrates at greater levels than sedentary individuals do.
carbohydrate glycogen loading
Carbohydrate (Glycogen) Loading…
  • As stated earlier, the majority of CHO in the body is stored in the skeletal muscles and liver in the form of glycogen.
  • Physiologically, it is to the athlete’s advantage if the total amount of stored glycogen can be increased prior to a competition.
  • Athletes involved in aerobic sports, especially those with durations in excess of 60 minutes, benefit the most from an increased level of stored glycogen.
carbohydrate glycogen loading1
Carbohydrate (Glycogen) Loading…
  • Essentially, the process of CHO loading involves the systematic decrease of dietary CHO intake in conjunction with a significant increase n exercise intensity.
  • Early procedures for CHO loading were particularly Spartan in nature, requiring multiple days of intense exercise (depletion phase) combined with dietary restriction of CHO intake.
carbohydrate glycogen loading2
Carbohydrate (Glycogen) Loading…
  • Ironically, although such protocols often did result in an increase in stored glycogen, the negative impacts often outweighed the benefits in performance.
  • These included severe physical fatigue associated with the depletion phase, along with negative emotional changes such as hyperirritability.
  • In addition, another problem related to CHO loading is that for ever gram of CHO stored, an additional 2.7 g of water is also stored.
  • As such, the process of CHO loading results in an overall increase in body weight that, in sports such as distance running, may represent a performance detriment.
carbohydrate glycogen loading3
Carbohydrate (Glycogen) Loading…
  • Research verified that a properly executed regimen of CHO loading can boost the level of stored glycogen from the normal 1.7 g of glycogen/100 g of muscle tissue to 4 to 5 g of glycogen/100 g of muscle tissue.
  • A typical modified regimen begins approximately one week prior to competition and includes a gradual tapering of physical activity accompanied with a slight increase in CHO ingestion.
  • Exercise (75% maximal O2 consumption over the first 3 days follows a steady decline in total time 1.5 hrs/day to 50 mins) while CHO consumption is maintained at 50% of total caloric intake.
carbohydrate glycogen loading4
Carbohydrate (Glycogen) Loading…
  • Over the next 3 days, exercise time is decreased to about 10-15 minutes while CHO consumption is increased to 75% of total caloric intake.
  • A normal protein and fat intake is maintained.
  • A high-CHO meal is then consumed on the day of the competition (McArdle et al., 2009)
carbohydrate and exercise
Carbohydrate and Exercise
  • CHO stored in muscle and liver as glycogen
    • -350 grams in muscle; - 90 grams in liver
    • -1800 calories in all
    • Trained muscle can carry more glycogen
    • Small amount circulating as blood glucose
  • Excess CHO stored as fat when glycogen stores are full

(Jon Vredenburg, MBA, RD, CSSD, LD/N, HFS)

carbohydrate and exercise1
Carbohydrate and Exercise
  • High intensity makes CHO the preferred substrate.
  • 50-60% of energy over 1-4 hours of continuous (70% capacity) exercise comes from CHO.
  • Since CHO is a primary fuel source – low levels lead to fatigue.
    • Fatigue = when exercise continues to the point that compromises liver and muscle glycogen supply.
    • 2 hour strenuous workout can deplete liver and muscle glycogen.
    • (Jon Vredenburg, MBA, RD, CSSD, LD/N, HFS)
carbohydrate and exercise2
Carbohydrate and Exercise
  • Rate of ingested carbohydrate oxidation is limited to -60 grams per hour (240 calories).
    • Intestinal transports become saturated.
    • CHO combinations (i.e. glucose +fructose) have greater oxidation rates.
  • Overall carbohydrate oxidation rates usually well above 500 calories/hour.
    • In moderate to higher intensity activities.
    • Clarifies the need for adequate fueling throughout training cycles (between sessions)
      • Jeukendrup. A (ED) (2010). Sports Nutrition from lab to kitchen, Meyer & Meyer Sport
where the fuel could be used
Where the fuel could be used…

*Brain storage has 20% at rest

fat lipids
Fat (Lipids)
  • Fats serve a variety of functions in the body, including:
    • Providing energy for muscle contraction
    • Insulation
    • Primarily in the form of subcutaneous fat
    • Protection of vital organs such as the kidneys and heart
  • Dietary fats are either simple or complex, depending on their specific molecular structure.
  • Fats, like CHO, consist of carbon, hydrogen and oxygen atoms; however, the ration of hydrogen to oxygen is far greater in fats than in carbohydrates.
fat lipids1
Fat (Lipids)
  • Depending on their molecular structure, fats can exist either in liquid (oils) or solid form.
  • Simple fats consist of two compounds:
    • Glycerol
    • Fatty acid
    • Can be either saturated or unsaturated
fat lipids2
Fat (Lipids)
  • The term saturated describes the fact that in this form of fat all of the available bonding sites on the fatty acid molecule are occupied by a hydrogen atom.
  • Most dietary sources of saturated fats are derived from animal sources (i.e. beef, pork, poultry, and dairy products) and are generally solid at room temperature.
fat lipids3
Fat (Lipids)
  • Unsaturated fats, as the term implies, are structured in such a way as to prevent all of the available bonding sites from being occupied by a hydrogen atom.
  • The majority of unsaturated fats exist in two forms, monounsaturated and polyunsaturated.
fats lipids
Fats (Lipids)
  • Monounsaturated fat
    • Include a single site on the carbon chain where a double bond exists, thus preventing hydrogen atoms from bonding at the site.
  • Polyunsaturated fats
    • Have two or more double bonds and, as such, have at least two sites that cannot be occupied by hydrogen atoms
fat lipids4
Fat (Lipids)
  • The recommended percentage proportion of fats in the diet should be 30% or less of the total calories consumed daily (McArdle et al., 2009).
  • It is recommended that saturated fats make up only 10% of total fats (20-25g based on 2000 – 2500 kcal/day); therefore, the majority of fats consumed should be unsaturated.
  • This helps avoid the problems attributed to excessive consumption of saturated fats, including high cholesterol and cardiovascular disease.
fat lipids5
Fat (Lipids)
  • Dietary sources of fats, as stated earlier, are animal products such as beef, poultry, and pork.
  • Other sources include dairy products, such as milk, butter, and cheese.
  • In addition, plant sources of fats include nuts and plant oils such as corn oil, olive oil, and soybean oil.
fat lipids6
Fat (Lipids)
  • In addition to CHO, fat is an important source of energy during rest and exercise.
  • Both CHO and fats are oxidized for energy at the same time.
  • The proportion of energy that comes from CHO and fats is dependent on the duration, intensity, and type of exercise as well as the athlete's fitness level and meal eaten prior to exercise (Manore et al., 2009).
  • Regardless of the type of fat consumed, all forms provide approximately 9 kcal/g; therefore, fats are calorie dense.
fat lipids7
Fat (Lipids)
  • One tablespoon of butter has the same kilocalories as 4 cups of chopped broccoli (100 kcal).
  • The available amount of energy in the form of stored body fat is significantly greater than what is available from CHO.
  • For example, the available energy in a 70-kg person who has 18% body fat is calculated to be around 113,400 kcal.
fat and exercise
Fat and Exercise
  • Potentially unlimited source of fuel during aerobic exercise.
    • 150 pound (68 kg) runner in a marathon at a 8 min/mile pace burns 3245 kcal.
    • One pound of fat = 3500 kcal.
  • Improving fatty acid oxidation during exercise preserves muscle glycogen.
    • Result of training adaptations.
fat burning simplified
Fat burning, simplified…
  • Fatty acids broken down in the mitochondria generate Acetyl CoA entry in the Kreb’s (TCA) cycle.
  • Accumulation of Acetyl CoA occurs in absence of carbohydrate.
    • Physical activity becomes compromised
    • Carbohydrate substrates needed to sustain Kreb’s Cycle
  • Fat burns in a carbohydrate flame
  • As with both carbohydrates and fats, proteins also contain carbon, hydrogen, and oxygen atoms in their molecules.
  • However, proteins also include nitrogen and, as such, they are unique molecules compared to the other nutrients.
  • Protein molecules are assembled by combining amino acids using peptide bonds to form large, complex molecules.
  • The majority of the body’s protein is found in muscle and connective tissues.
  • Proteins are also found in the body fluids and in the blood from thousands of different enzymes and structures related to blood clotting such as fibrin and fibrinogen
  • In addition, muscle protein is used as an energy source during prolonged exercise, producing as much as 10% to 15% of the energy requirements for long duration activity.
  • Research suggests that a regimen of regular aerobic exercise enhances the body’s ability to generate energy from the metabolism of proteins (Sumida & Donovan, 1995).
  • The body builds proteins from the amino acids that are available from the protein that is consumed in the diet.
  • Of the 20 amino acids required to construct the body’s proteins, 8 cannot be synthesized by the body and must, therefore, be ingested in the diet.
  • These eight amino acids are known as “essential,” implying that they must be present in the diet.
  • They are isolucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
  • The best dietary sources of the essential amino acids are eggs, meats, and dairy products, all known as complete proteins.
  • Incomplete proteins are those that lack one or more or contain insufficient amounts of one or more of the essential amino acids.
  • They include foods found in the legume and grain categories.
  • 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.
  • Substance in foods made up of chains of amino acids (AA)
    • Three categories of AA:
      • Essential
      • Nonessential
      • Conditional
    • Build, repair and maintain body tissues
    • Provide energy if carbs and fats are in short supply
    • 4 calories per gram
protein supplementation
Protein Supplementation…
  • Because dietary protein is associated with building muscle mass, many athletes are curious about the benefits of extra protein consumption beyond that found in regular diets.
  • A recent study of 61 high school football players reports that 64% are ingesting protein supplements in an attempt to gain strength or improve performance (Duellman et al., 2008).
  • Unfortunately, the researchers also present the more than 60% of these athletes believe there are no risks to excessive protein intake.
protein supplementation1
Protein Supplementation…
  • However, at least two problems are associated with the practice of consuming additional protein.
    • The first is that many sources of dietary protein also contain a large amount of saturated fat, such as beef and pork products.
    • The second problem is that in certain cases the body may be unable to eliminate the by-products of excess protein breakdown efficiently, and, as such, organs such as the liver and kidney are stressed.
protein supplementation2
Protein Supplementation…
  • Today there is a huge commercial market for what are commonly known as protein supplements, often sold at health food stores, grocery chains, and sporting good stores and through mail order and the Internet.
  • Most of these products consist of meat by-products that are processed into a powder form that is then mixed with water or some other liquid and consumed orally.
  • Unfortunately, because these products are marketed as food supplements, their purity is not monitored by the Food and Drug Administration.
protein supplementation3
Protein Supplementation…
  • In addition, many of them are extremely expensive on a per-pound basis, often exceeding the cost of more common sources of protein such as meat and dairy products.
protein supplements
Protein Supplements…
  • Unfortunately, there is virtually no scientific research that supports the premise of protein supplementation enhancing muscle development.
  • Muscle mass does not increase simply by eating high-protein foods or special preparations of amino acids (McArdle et al., 2009).
protein supplements1
Protein Supplements…
  • At present, available research indicates athletes involved in intense training, particularly strength training, need to consume between 1.2 g and 1.8 g of protein for each kilogram of body weight, whereas the sedentary person or light exerciser needs to consume only 0.83 – 1.2 g/kg.
  • To put this into a practical context, the calculated protein requirements for a 60-kg would range from 72g to 108g per day.
  • Eight ounces of broiled salmon provides approximately 62 g of protein, 8 ounces of lean sirloin steak provides approximately 65 g of protein, and 8-ounce skinless chicken breast yields a little over 70 g of protein
protein supplements2
Protein Supplements…
  • It can be seen that adequate protein to meet the daily requirements of an athlete in heavy training can easily be achieved through meals without the need of additional supplements.
  • Only growing infants and children, pregnanat or nursing women, or adults suffering from certain disease or injury states should consume more than the recommended amount (McArdle et al., 2009).
proteins and exercise
Proteins and Exercise
  • Protein used for growth and repair of tissue.
    • If overall caloric intake is adequate
  • Protein energy contribution to exercise inversely proportional to available energy stores.
    • Usually accounts for a small (>5%) amount of ATP formed during endurance activity
  • Vitamins are chemicals that are needed by the body in relatively small amounts and, therefore, are classified as micronutrients.
  • This should not be interpreted, however, to mean that vitamins have little importance nutritionally.
  • On the contrary, adequate amounts of vitamins are essential to health and human performance.
  • Vitamins serve a multitude of functions in the body, essentially helping to regulate biochemical reactions such as energy metabolism and cell and tissue generation, as well as serving antioxidants (antioxidants protect structures such as cell membranes from the damaging effects of free radicals that are released during vigorous exercise).
  • Vitamins contain no caloric value and, as such, do not directly provide energy for muscle contraction.
  • So far, 13 specific vitamins have been identified and are divided into two groups:
    • Water soluble
    • Fat soluble
  • Water-Soluble group includes:
    • Vitamin C (ascorbic acid)
    • The B vitamins
      • B1, B2, B6, B12
      • Niacin
      • Folic acid
      • Biotin
      • Pantothenic acid
  • Water soluble vitamins, with the exception of B12, are not stored in the body, and excess amounts are excreted via the kidneys and urine.
  • Fat-soluble vitamins:
    • Vitamins A, D, E, K
    • Because of their solubility, they are stored in the fat tissues of the body.
    • In fact, excess consumption of fat-soluble vitamins beyond what is recommended (in the United States Allowance [RDA]) can result in buildup of and eventual toxic reaction to the stored vitamin (McArdle et al., 2009).
  • There is no evidence that taking any vitamin in an amount greater than the recommended level provides any sort of performance enhancement.
  • Athletes who consume balanced diets most likely are getting adequate amounts of vitamins through their food and beverage consumption.
  • For athletes who are eating less than an ideal diet, a daily multivitamin supplement that meets the RDA’s for all necessary vitamins is advised.
  • There is no evidence that vitamins marked as organic or natural provide any benefit over those that are manufactured synthetically and often sold at a lower cost.
  • To be effective, vitamins should be taken after meals to optimize absorption because they work best in the presence of other nutrients.
  • Key regulators in energy metabolism
  • Offer protection against oxidative damage
  • Supports growth and development
  • If take too many may have a reverse effect
  • Minerals are elements that must be consumed regularly to ensure normal body functions.
  • They provide structure, help maintain normal heart rhythm, assist muscle contractility, promote neural conductivity, and regulate metabolism (McArdle et al., 2009).
  • A typical over-the-counter daily vitamin and mineral supplement usually includes many minerals.
  • As is the case with vitamins, there is no scientific evidence that consuming minerals in excess of the RDA provides that advantage in performance.
  • In addition, a well balanced diet can provide all the necessary dietary minerals.
  • The best known minerals are iron and calcium.
  • Perron and Endres (1985) investigated the nutritional habits of 31 female high school volleyball players.
  • Seventy percent (70%) of them did not meet the RDAs for energy (total calories), calcium, and iron.
  • Iron is associated with red blood cell formation, oxygen storage and transport, and enzymatic reactions related to protein and carbohydrate metabolism.
  • Iron is available from plant and animal sources.
  • It is best absorbed from animal sources.
  • RDA for iron is 10 mg for males and 18 mg for females.
  • Females require more iron than males, especially during their first menstrual cycle.
  • Inadequate intake of iron or limited rates of iron absorption can cause anemia, resulting in lethargy and shortness of breath.
  • Physically active individuals need only include the RDA levels of iron in their daily diet; they should steer clear of supplements unless a deficiency exists because excess iron can be very toxic to the body (McArdle et al., 2009).
  • However, endurance, vegetarian, and female athletes may want to consult a physician for assessment and maintenance of proper iron balances.
  • Current thought among sports scientist is that iron deficiency is common in athletes involved in endurance sports (Pattini & Schena, 1990).
  • It is speculated that iron may be lost through sweating, gatrointestinal bleeding, menstrual bleeding, and excessive red blood cell distribution (hemolysis) in the blood vessels.
  • A convenient method of supplementation is a daily multivitamin and mineral tablet.
  • Numerous products are available over the counter that provide the adult RDA of iron.
  • Calcium is metabolically associated with normal bone and dental health.
  • It is the most prevalent mineral in the body and is easily obtained in the diet by consuming diary products or other foods/beverages that have been artificially fortified with calcium.
  • Scientific evidence suggests that some groups of athletes may be at an increased risk of calcium deficiency (Deuster et al., 1986; Moffatt, 1984).
  • Female athletes involved in aerobic running sports, as well as gymnasts, have been found to be consuming too little calcium.
  • This places these people at risk for inadequate bone development and can contribute to osteopenia or osteoporosis in later life.
  • In these high-risk groups, calcium supplementation is most certainly warranted.
  • Again, it is important to note that a supplement that provides the RDA is appropriate because consuming calcium in excess of this level may lead to other problems.
  • The recommended daily dosage for adolescent females is 1500 mg.
  • Serve as structural components of the body
    • Major minerals and trace minerals
  • Stimulate muscle and nerve activity as well as hemoglobin synthesis
  • Electrolytes regulate fluids in and out of the cells
    • Sodium and Potassium
  • Maintain relative acidity or alkalinity of blood and tissue
    • Control acid-base balance
  • There is virtually no debate in the sports medicine community regarding the importance of water, not only to human performance but to survival as well!
  • Water serves myriad functions in the body because the molecule is necessary for cellular function, heat regulation, and elimination of waste products.
  • Housed in two general locations:
    • Are extracellular fluids
      • Those fluids outside of the cells, commonly called interstitial fluid.
    • Intracellular fluids
      • Those fluids contained in the cell.
  • Water is constantly being lost through normal body functions such as breathing, elimination of wastes, and sweating.
  • At rest the adult requirement for water is approximately 2.5 L of water daily.
  • Under conditions of heavy exercise, especially in conditions of high ambient temperature, water requirements can escalate to 5 L to 10 L daily (McArdle et al., 2009).
  • During exercise, a significant amount of body water is lost to eliminate metabolic heat.
  • The circulatory system transports this excess heat by way of the blood to the skin, where, in harmony where the body’s sweat glands, heat is carried from the surface by way of evaporation.
  • The process of sweat evaporation from the skin surface can easily result in an hourly water loss from the body of 2 L or more for each hour of exercise.
  • The most serious consequence of profuse sweating is the loss of body water.
  • A reduction of body weight of 2-5% can result in reduced performance and stress on internal organs.
  • To calculate the reduction in body weight due to fluid loss, weigh the athlete before and after practice.
  • Take the number of pounds lost in activity and divide the number by the pre-practice weight.
  • This fluid must be replaced, or serious, even life-threatening, consequences can result.
  • Current recommendations suggest that for every pound of water weight lost, an athlete should consume 20 – 24 oz of fluid (McArdle et al., 2009).
water summary
  • One of the most important nutrition practices for enhancing performance.
  • Even a 2% water deficit can impair performance.
  • Hydration status influenced by:
    • Fitness
    • Intensity
    • Temperature
    • Clothing
    • acclimation.

Jeukendrup. A (ED) (2010). Sports Nutrition from lab to kitchen, Meyer & Meyer Sport

water summary1
  • Proper hydration = drinking enough fluid to minimize loss of body weight without overdrinking.
  • There is no ‘one fits all’ amount
  • Weight (in pounds) / 2 = Ounces Water needed at rest
    • General guideline

Jeukendrup. A (ED) (2010). Sports Nutrition from lab to kitchen, Meyer & Meyer Sport

sweat composition
Sweat Composition…
  • Physical activity produce heat, and this heat must be dissipated.
  • Sweat contains electrolytes such as sodium chloride, potassium, calcium and magnesium.
  • 1 liter of sweat could contain up to 2 grains of sodium
    • Potential for sodium imbalance main concern
    • Cramping intervention
    • Bernadot, D. (2006). Advanced Sports Nutrition
sweat mineral composition
Sweat Mineral Composition
  • Sodium 460-1840 mg/L
  • Chloride 710-2840 mg/L
  • Potassium 160-390 mg/L
  • Magnesium 0-36 mg/L
  • Calcium 0-120 mg/L
  • Dunford. M. (Ed). (2006) Sports Nutrition: A practice mineral for professionals
hydration guidelines
Hydration Guidelines…
  • Before exercise: Drink 12-24 oz of fluid 2 hours prior to exercise and 15 minutes
  • During exercise: Drink 8-10 oz of cold water or sports drink every 15 minutes during exercise to delay fatigue
  • After exercise: drink 20-24 oz of water or sports drink for every 1 pound of sweat lost
  • Source: American College of Sports Medicine.
extreme conditions
Extreme Conditions…
  • Physical fitness dictates heat tolerance
    • High body fat = poor heat tolerance
    • Problems typically happen early in new training schedules
    • Have an emergency action plan (EAP)
    • Acclimatization: adaptations by the body to reduce the physiological strain from the environment (hot or cold)
      • Sweat starts at a lower core temperature
      • Reduction in salt losses in sweat; more sweat produced
      • Typically takes two weeks
sports drinks
Sports Drinks…
  • Contain carbohydrates for energy and electrolytes for repletion
    • Adding protein has had equivocal results
  • Many flavors and variations
    • 8 ounce serving
      • 50 calories
      • 14 g CHO
      • 110 mg sodium
      • 30 mg potassium
      • Saunders, M. Kane. M (2004). Effects of a carbohydrate-protein beverage on cycling endurance and muscle damage.
sports drinks1
Sports Drinks…
  • The best sports drink will replace what is being lost during activity
  • Cool and non-carbonated
  • Sodium
    • Provides the drive to drink; maintains proper sodium balance
  • CHO
    • At concentrations above 7% gastric emptying time reduced
    • High CHO content leads to GI distress
    • Multiple CHO sources seem to facilitate absorption
    • Maltodextrins used to enhance palatability (less sweat)
sports drink vs water
Sports Drink vs. Water
  • Water is suitable for most recreational activities of short duration (<60 minutes)
  • As intensity and duration increase sports drinks are preferred
  • Exogenous energy source aids performance
sweat rate
Sweat Rate…
  • Amount of sweat lost in an hour
    • Determine pre-exercise weight
    • Determine number of fluid ounces consumed during activity
      • 16 oz = 1 pound
    • Determine post-exercise weight
    • Provides individualized guidance
    • Sweat Rate = [Pre-Exercise Weight – Post-Exercise Weight] + Fluids consumed/Time (hours)
  • Helps athlete prepare for next exercise bout (i.e., training camp, frequent training)
  • Under-hydration likely since sweat losses typically exceed consumption and absorption
  • Rehydrate with an amount greater than the losses
special considerations female athletes
Special Considerations..Female Athletes…
  • As more women become involved in organized sports, concerns have been raised regarding special nutritional considerations for female athletes, especially those involved in sports that place an emphasis on being lean, such as gymnastics.
  • Perron and Endres (1985) find that 81% of female volleyball players report a concern about body weight; perhaps their low caloric intake was part of an attempt to lose weight.
special considerations female athletes1
Special Considerations..Female Athletes…
  • Loosli and Benson (1990) surveyed 76 adolescent female gymnast and their results indicate that these young athletes were consuming less than the RDA in a number of vitamins and minerals and were consuming too few total calories, especially in the form of carbohydrates.
special considerations female athletes2
Special Considerations..Female Athletes…
  • because gymnastics place great emphasis on being lean, it is not surprising that the majority of these girls demonstrated a deficient caloric intake and altered micronutrient consumption.
  • However, gymnastics is not alone.
  • It was also reported that 47% of athletes in “lean” sports (x-country, swimming/diving, crew-rowing, and cheerleading), in contrast to 20% in “non-lean” sports (basketball, softball and lacrosse), had clinical disordered eating, which includes calorie restriction.
x country and endurance sports
X-Country and Endurance Sports
  • Upgrove and Achterberg (1990) investigated the nutritional habits of male and female high school cross country runners.
  • Ironically, in a sport in which a diet high in carbohydrates is a prerequisite to success, these young runners were poorly versed in the role of this essential nutrient.
  • In addition, they reported that coaches were their preferred source of information on nutrition.
  • The sport of wrestling continues to be plagued with the problem of athletes practicing rapid, often unhealthy weight-loss procedures.
  • Wrestling is one of only a few sports that match participants on the basis of weight.
  • Yet, in an effort to gain an advantage, many wrestlers attempt to shed pounds rapidly to compete in a lighter weight category.
  • Unfortunately, the only form of rapid weight loss, short of surgical removal of tissue, is through dehydration.
  • Water weights approximately 7 pounds per gallon; therefore, an athlete can significantly reduce weight by reducing the body’s water content.
  • Wrestlers have been known to use a variety of methods to rapidly lose weight, including fluid restriction, the use of laxatives and diuretics, artificially induced sweating, and even starvation.
  • There is no definitive proof that such tactics actually present an advantage, and there are plenty of reasons not to engage in such behavior.
  • The short-term effects of repeated bouts of extreme, rapid weight loss include strength depletion, increased blood viscosity (blood thickening), blood clots, kidney and liver problems, swelling of the pancreas (which produces insulin), and ulcers (Nelson, 1989; Williams, 1992).
  • The long-term effects are not known at this time; however, there is speculation in the scientific community that these techniques may interfere with normal growth and development of the adolescent athlete.
  • In an effort to reduce the likelihood of unhealthy weight-loss practices (“weight cutting”) in high school wrestlers, the state of Wisconsin instituted the Wrestling Minimum Weight Project (WMWP) in 1989 (Oppliger et al., 1995).
  • This project involved the establishment of minimum weight-loss and body-composition criteria that limit all participants to a body fat minimum of 7% and a maximum of 3 lb of weight loss per week.
  • Many athletes do not consume the proper proportions of protein, carbohydrates, and fat. Athletes should consume diets that provide at least the RDA for all micronutrients.
  • Carbohydrate consumption should be 6-10 g/kg body mass (2.7-4.5 k/lb body weight). Carbohydrates maintain blood glucose levels during exercise and replace muscle glycogen. The amount required depends on the athlete’s total daily energy expenditure, type of sport, sex, and environmental conditions.
  • Protein recommendations for endurance and strength-trained athletes range from 1.2 to 1.7 g/kg body mass (0.5-0.8 g/lb body weight.) These recommended protein intakes can generally be met through diet alone, w/o the use of protein or amino acid supplements.
    • For example, to compute the recommended 1-day protein intake for an 85-lb female gymnast, make the following calculations:
      • Body weight in kilograms = 38.6
      • (85 lb / 2.2 lb per kg)
      • =46.4 g daily protein requirement
      • A chicken breast (8oz) will provide the protein requirement
  • Fat intake should range from 20% to 30% of total energy intake. Consuming less than or equal to 20% of energy from fat does not benefit performance because fat is a source of energy, fat-soluble vitamins, and essential fatty acids.
  • Athletes participating in sports that stress lean builds and low body fat tend to follow diets too low in total calories. Athletes who restrict energy intake, use severe weight-loss practices, or eliminate one or more food groups from their diet are at greatest risk of micronutrient deficiencies.
  • Athletes tend to consume too many calories in the form of junk food, which is laden with fat and extra protein.
  • Many athletes’ diets are deficient in at least some important minerals, such as calcium, iron, and zinc. However, the best sources are natural foods and not supplements unless specifically guided b y a physician. Short- and long-term supplementation above recommended doses does not improve exercise performance or training responses (McArdle et al., 2009).
exercise and metabolism
Exercise and Metabolism…
  • ATP is the energy currency of the body
    • Power output or frequency of muscle contractions determines demand.
  • Three different energy systems to get ATP
    • Phosphagen system
      • Very short term
    • Anaerobic system
      • Short term
    • Aerobic system
      • Unlimited capacity to make ATP
        • Hargreves, M & Spiret L (2006)
phosphagen system
Phosphagen System..
  • Used in short burst of exercise
  • Anaerobic production of ATP via stored phosphocreatine (PCr)
    • Phosphate group removed by creatinekinase
    • Limited amount of PCr stored in muscle tissue
  • Energy supply lasts about 8 to 10 seconds

McArdle W. Katch, F & Katch V (2005) Sports and Exercise Nutrtion

anaerobic glycolysis
Anaerobic Glycolysis
  • Also known as glycogen-lactic acid system
  • Stored glycogen is converted to energy
  • Can provide energy for about 90 – 120 seconds
  • ATP is made with pyruvate as an end product
    • Lactic acid is formed from pyruvate
    • ATP supplied quickly, but at a slower rate than phosphagen system
    • McArdle W., Katch F & Katch V (2005) Sport & Exercise Nutrition
aerobic system
Aerobic System
  • After – 2 min muscles (and the body!) need oxygen
  • With oxygen present, gerater yield of ATP
  • Fuel sources with aerobic respiration
    • Muscle glycogen
    • Liver glycogen
    • Exogenous fuel
    • Fatty acids, triglycerides (fats) and amino acids (proteins)
    • McArdle W., Katch F & Katch V (2005) Sport & Exercise Nutrition
eating for muscle
Eating for Muscle…
  • Adding lean muscle mass requires anabolism
    • Anabolism = constructive metabolism
  • Protein needs are increased to double RDA
  • Use meal frequency to educate (vs calorie counting)
  • McArdle W. Katch, F & Katch, V (2005). Sports & Exercise Nutriton
eating for muscle1
Eating for Muscle…
  • Gaining weight is constant work at the dining room table.
  • Fuel basal needs, activity and growth
    • Harder gainer or an under-eater?
    • Rapid weight gain may mean more fat deposition
    • “Bulk up” (lean mass) vs “bulk out” (fat mass)
additional tips
Additional Tips
  • feature calorie containing beverages with each meal and snack
  • Add ‘energy dense’ foods to the diet
  • Stack foods with add-ons
    • Potato with toppings
    • Dried fruit and nuts on cereal
  • Don’t drink water right before meals
  • Monitor caffeine to promote rest
  • Content adapted from: Litt, A (2004) Fuel for Young Athletes
adding energy dense foods
Adding energy dense foods
  • Choose This… Calories Over This… Calories

Cup of Granola 500 Cup of cheerios 90

Bag of Peanuts 170 Bag of pretzels 110

Sandwich on a sub

Roll 500 sandwich on bread 300

Bagel 330 english muffin 130

Sports Drink 20 oz 135 water 0

mistakes commonly made
Mistakes Commonly Made
  • These habits can impact overall energy intake/availability
  • Over-eat protein
  • Under-eat carbohydrates
  • No dietary variation
safe weight loss
Safe Weight Loss
  • Best pursued during an off-season
  • Look at both sides of the energy balance equation
  • Common recommendation:
    • 1-2 pound per week decrease
  • Larger mass athletes prone to weight management problems
    • Greater number and volume of adipose cells

Are there ‘bad’ foods?

    • General rule of thumb: The less processed it is, the better nutritional benefits you will receive.
menu planning
Menu Planning
  • Fueled muscle beats under-fueled muscle
  • Pre-exercise meals
    • Give ample time for digestion
    • Provide the correct fuel matrix
      • CHO, Lean protein, low fat, low fiber
    • Minimize potential GI stressors
    • Stress food safety
    • Know their tastes
    • Know your budget
menu planning1
Menu Planning
  • Early events
    • Top off liver glycogen to prevent ‘bonking’
    • Try primary meal late in the day prior to competing AND light snack the morning of even (1-2 hrs. before)
during exercise
During Exercise…
  • Replace fluid losses
  • Exogenous CHO typically not necessary in events 45 minutes or less
  • Endurance: Provide CHO to maintain blood glucose levels and for exogenous energy
    • 30-60 g CHO/hr (common fuels used in endurance events: jellybeans, gels, energy bars, sports drinks)
    • Begin intake shortly after activity begins
    • 80-90 g CHO/hr for ultra endurance (> 3 hours)
      • Multiple transportable carbs
      • Position statement of the American diabetic association, dietitians of Canada
common cho amounts
Common CHO amounts
  • 32 ounces sports drink = 60 g
  • 4 fig cookies = 42 g
  • Energy bar = 45 g
  • Banana = 30 g
  • Carb gel pack = 28 g
  • Handful of pretzels = 25 g
recovery nutrition
Recovery Nutrition…
  • After exercise, dietary goals are to replace muscle glycogen and ensure quick recovery.
  • Composition and timing of the recovery meal or snack depend on the length and intensity of the exercise session (ACSM, 2009).
  • Glycogen depletion can occur after 2-3 hours of exercise at 60-70% VO2 max
  • Meals need to provide adequate fluids, electrolytes, carbohydrates, and protein.
  • A carbohydrate intake of approximately 1.0-1.5 g/kg body mass during the first 30 minutes and again every 2 hours.
recovery nutrition1
Recovery Nutrition…
  • The timing of CHO ingestion is important because glycogen levels replenish faster if the food is consumed within 30 minutes to 1 hour.
  • The type of food is also significant because consumption of high glycemic index CHOs results in higher muscle glycogen levels 24 hours after a glycogen depletion exercise as compared with the same amount of low glycemic index carbohydrates.
  • Protein consumed after exercise provides amino acids for building and repair of muscle tissue (ACSM, 2009).
recovery nutrition summary
Recovery Nutrition Summary
  • Replace the glycogen that was used
    • Can take 24 hours to fully reload
  • Glycogen replacement is spurred post exercise
  • Timing of meal less critical if 1-2 days rest are upcoming
    • As long as regular intake resumes in the 24 hour period afterwards
sport specific guidelines
Sport Specific Guidelines
  • Soccer/Basketball/Hockey/Lacrosse/ect..
  • High energy demands
    • Caloric expenditure can be over 1500 calories/game
  • Blood flow to the gut decreased (w/intensity)
  • Higher CHO needs in-season/training
  • Recovery critical with tournament play
    • Replenish glycogen immediately following matches
    • Prevents fatigue as season/training progresses
    • Dunford. M. (Ed). (2006) Sports Nutrition: A practice manual for professionals
sport specific guidelines1
Sport Specific Guidelines…
  • Baseball
  • Relatively low energy demands
  • Prone to weight gain
    • Skipped meals due to schedules
    • Increased availability of high energy foods
  • Dehydration a concern due to hot and humid conditions
sport specific guidelines2
Sport Specific Guidelines…
  • Football:
  • Energy needs high to maintain weight, but (relative) energy expenditure during activity not as high.
  • High training/competition requires exogenous carb to offset fatigue.
sport specific guidelines3
Sport Specific Guidelines
  • Endurance Sp0rts:
  • Uses the complete range of energy systems
  • Fluid consumption with sports drinks
    • Primarily for the 2hr + events
    • If using CHO gels – you need water too
  • Snack frequently on high carb foods day before races
    • Some athletes report limiting fiber and spicy foods helps settle gut
    • Liberal sodium use, if needed
  • ‘Practice’ eating habits before put to race day use
    • Dunford. M. (Ed). (2006) Sports Nutrition: A practice manual for professionals
sport specific guidelines4
Sport Specific Guidelines
  • Endurance Sports:
  • CHO loading guidelines:
    • High CHO diet with a reduction in training
  • You can expect about a 2-4 total pound weight gain with proper CHO loading
    • One part glycogen to three parts stored water
  • Protein also catabolized for energy
    • 1.5 g/kg/day recommendation
    • Clark N. (2003). Nancy Clark’s Sports Nutrition Guidelines
sport specific guidelines5
Sport Specific Guidelines…
  • Swimming:
  • High volume training programs are common
    • Adjust intake to training season demands
  • Fluid losses still occur, but generally less than ‘dry land’ athletes
  • Organize nutrient intake around training
    • Sports drinks, gels, energy bars, liquid meal supplements
    • Multiple events = need recovery plan

Jeukendrup. A., (ed). (2010). Sports Nutrition: From lab to Kitchen, Meyer and Meyer Sport

sport specific guidelines6
Sport Specific Guidelines
  • Recreational athletes
  • Educate on pre-hydration and re-hydration
  • Recovery meal timing likely not as crucial
  • Educate on caloric expenditure realities
    • Prevents over compensation & weight gain
  • May require Fast food meal planning
  • Activity:
    • Identify the best menu choice for recovery from the given menu for a 80 kg athlete
recap menu planning across a spectrum of training
Recap: Menu Planning Across a Spectrum of Training
  • Examine energy expenditure & schedules
  • Load up on the produce
    • Minimum of 9 servings of fruit and vegetables daily for those in heavy training
  • Maintain a good hydration plan
  • ‘Practice’ new eating regimens before competing with them
nutrition supplements
Nutrition Supplements…
  • Supplement is defined as something added to complete a thing, make up for a deficiency, or to extend or strengthen the whole.
  • A nutrition supplement cannot replace a healthy diet
why supplement
Why Supplement?
  • Gain a perceived ‘edge’
    • Improve health or prevent illness
    • Change body composition
    • Improve performance
  • Supplement industry sales in 2011: $30 billion (Nutrition Business Journal, 2012)
  • Rate of growth of 7% annually
dietary supplement health and education act
Dietary Supplement Health and Education Act
  • Passed in 1994
  • Product is a…..
    • Vitamin
    • Mineral
    • Herb or other botanical
    • Amino acid
    • Dietary substance
    • Concentrate or metabolite of any of the above
structure and function claims
Structure and Function claims…
  • “This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.”
    • Strengthen
    • Improve
    • Protect
    • defent
2002 international olympic committee ioc study
2002 International Olympic Committee (IOC) Study
  • 94 of the 634 samples studied contained substances not listed on the label that would trigger a positive drug test
    • From 12 different countries
  • U.S. supplements tested (45 of 240) had a 18.8% fail rate
popular sports supplement review
Popular Sports Supplement Review…
  • Beta Alanine
  • Non-essential amino acid
  • Serves as the substrate for carnosine
    • Acts as a buffering agent for lactic acid
    • Supplementation can increase muscle carnosine levels
  • Marketed to enhance weight training and high intensity training
  • Possibly effective – more research needed on safety
    • Reported side effect of paresthesia


  • Strongest evidence is that it enhances endurance performance
    • CNS stimulant
    • Decreased perception of effort
  • In moderate doses is NOT a diuretic
  • Amount needed for enhanced performance equivalent to 2-3 mg/kg
    • Trial and error
    • Approx 2 cups of coffee


  • Ganio et al (2009) found that abstaining from caffeine at least 7 days before use will give the greatest chance of optimizing the ergogenic effect
  • Gliottoni et al (2009) found that caffeine can help mitigate sensations of pain during exercise

Caffeine….not for everybody!

  • monitor for side effects:
    • Increased heart rate
    • Nervousness
    • GI problems
      • If not a regular user
      • High doses (>6 mg/kg) do not lead to further performance enhancements and are potentially problematic.


  • Found in small amounts in beef and fish
  • Helps to replenish ATP reserves in the muscles
    • Provides energy via phosphagen system
    • Increases rate of phosphocreatinesysthesis
  • Generally appears safe and effective
  • Seems to enhance muscle performance during repeated bouts of brief, high-intensity exercise
  • ACSM recommends that it is NOT USED by children under the age of 18
  • Hydration needs to be addressed
    • Pulls water into muscle cells

Energy Drinks:

  • Appeal to athletes
    • Nutrient profiles vary
    • 25 grams of carbs/8oz serving; along with the caffeine, herbal stimulants
  • Consumed prior to exercise can lead to GI distress
  • Caffeine and the herbal stimulant amounts are a concern – especially in younger populations
  • Stresses heart rate and can lead to heat illness
the color code
The Color Code
  • RED – Higher in saturated fat and calories
    • Use in moderation – these can slow you down
  • Yellow – a moderate amount of fat and/or heavy processed
  • Green – the leanest selections of protein and/or healthier a CHO
    • High performance foods
  • “Think about fuel and hydration as part of your internal equipment. You can’t show up to practice and be strong, be quick, and last long without pre-fueling.”
    • Leslie Bonci, MPH, RD, CSSD, LDN
    • Pittsburg Steelers