Chapter 6

Nutritional Considerations

Nutrition

• Diet influences every aspect of sports participation

• *

• Recovery from training and competition

• *

• Recovery from injury (to some extent, the likelihood of injury)

• Certified athletic trainers are typically more knowledgeable about nutrition than coaches.

• Coaches and athletes often lack adequate nutrition information and incorporate unfounded nutritional practices into training programs.

• 6 classes of nutrients that we will cover in this chapter

• Macronutrients (required in large amounts)

1. Carbohydrates

2. *

3. Proteins• Micronutrients (required in small, or trace amounts)

4. *

5. Minerals

6. *

CarbohydratesCarbohydrates (CHO) provide energy for high-intensity

exercise.

• Specific forms of CHO used within the body are blood glucose and glycogen (the storage form of glucose) found in the liver and skeletal muscle.

• A carbohydrate is made up of a carbon, hydrogen, and oxygen atom, with the number of carbon atoms ranging from 3 to 7.

Categories of Carbohydrates1. Monosaccharides (the simplest form, single molecule)

• *

• *

• Galactose

2. Disaccharides (2 monosaccharide molecules combined)• Lactose (milk sugar)

• *(most common sugar in the diet)

• *

3. Polysaccharides (10 to thousands of monosaccharides combined)

• Glycogen

• *

• Cellulose

Carbohydrates

• The most common forms of dietary CHO intake are from simple sugars (foods high in fructose) such as soft drinks, candy, and high sugar cereal.

• High in caloric content, these foods provide little in the way of other nutrients, and are therefore called “empty calories”.

Sources of Carbohydrates1. *– a superior form of CHO.

• The CHO in these foods is in the form of starch (a complex carbohydrate)

• Complex Carbohydrates often contain dietary fiber which may lower cholesterol absorption and is beneficial to the digestive system.

2. *• Provide CHO in the form of fructose (monosaccharide) is

sweeter than sucrose, and it “does not stimulate pancreatic insulin secretion” and therefore “helps to stabilize blood-glucose and insulin levels”.

• *

Carbohydrates and Your Diet

• CHO in the diet should range between 60% and 70% of the total calories consumed daily (depending on the exercise intensity)

• Regardless of the type of CHO, they all provide approximately *• A kilocalorie (kcal) is the energy equivalent required

to raise the temperature of 1 kilogram of water by 1 degree Celsius)

• *

Carbohydrate (Glycogen) Loading

• Where is the majority of CHO stored in the body? In the skeletal muscles and liver as glycogen!

• Therefore, it is to the athlete’s advantage physiologically to increase the amount of stored glycogen prior to competition!

• *• Typical regime begins approx 1 week prior to competition

• High-intensity exercise, high protein, low CHO diet for the first 4 days

• Days 5-7 consist of high CHO and normal protein diet• High CHO meal is consumed on the day of competition

Fats (Lipids)Fats (lipids) are needed for a variety of reasons:

• Provide energy for muscle contraction• *• *(kidneys and heart)

Dietary fats are either simple or complex• Consist of Carbon, Hydrogen, and Oxygen atoms

(like CHOs) but the ratio of Hydrogen to Oxygen is far greater in fats

• *

Simple Fats• Consist of 2 components (glycerol and a fatty acid)• Can be either saturated or unsaturated• Saturated (all the available bonding sites on the fatty acid

molecule are occupied by a hydrogen atom.• Most saturated fats are from animal sources (beef, pork,

poultry, and dairy products)• *

• Unsaturated (prevents all available bonding sites from being occupied by a hydrogen atom)• *• Recommended that the majority of fats consumed be

unsaturated to avoid the problems attributed to excessive consumption of saturated fats related to cardiovascular disease

Fats in Your Diet

• Fats in the diet should be * of the total calories consumed daily.

• Recommended that saturated fats make up only * of total fats

• Regardless of the type of fat, they all provide approximately *

• The available amount of energy in the form of stored body fat is significantly greater than what is available from CHO.

• *

Energy and Consumption of Fat-Containing Foods

FOOD SERVING SIZE ENERGY (kcal) Fat (g)

Milk, whole 8 oz 150 8.2

Milk, 1% 8 oz 102 2.6

Peanut Butter 1 tbsp 111 9.1

Cookies, Oreos 3 cookies 160 7.0

Apple 1 medium 81 0.5

Avocado 1 medium 324 29.0

Strawberries 1 cup 45 1.0

Ground Beef 3 oz 231 15.5

Chicken Breast 3 oz 140 3.1

ProteinsProteins also contain carbon, hydrogen, and oxygen

molecules, but also contain nitrogen (makes them unique)

• Assembled by combining amino acids; 20 specific amino acids required in the body to produce thousands of proteins

• *• Muscle protein is used as an energy source

during prolonged exercise; produces as much as 10% to 15% of the energy requirements

• *

Proteins

• The body builds proteins from the amino acids that come from the protein consumed in the diet

• Of the 20 amino acids required to make the body’s protein, 8 cannot be synthesized by the body and must be ingested in the diet

• 8 essential amino acids:1. Isoleucine

2. *

3. Lysine

4. *

5. Phenylalanine

6. *

7. Tryptophan

8. *

Protein SupplementationProtein supplementation is not recommended because

the excess can:• *• *

• NO scientific evidence that protein supplements enhance muscles (not regulated by the FDA)

• During intense training, 1.2 to 1.8 grams of protein/kg body weight are recommended.

• *

VitaminsVitamins have various functions:1. Help regulate metabolism2. *3.Some serve as antioxidants (protect structures such

as cell membranes from the damaging effects of free radicals that are released during vigorous exercise)

• *

Types of Vitamins

Water-Soluble Vitamins

• C• *• B2• B6• B12• *• Folic Acid• *• Pantothenic Acid

Fat-Soluble Vitamins

• A• *• E• *

How Many Vitamins??• * vitamins are not stored in the body and excess amounts

are excreted via the kidneys and urine

• * vitamins are stored in the fat tissues in the body. Excess consumption can result in buildup and an eventual toxic reaction to the stored vitamin

• *

• Athletes consuming a balanced diet are most likely getting adequate amounts of vitamins

• *

MineralsMinerals are elements needed for various body

functions.• * is most prevalent mineral in body.• There is no scientific evidence to support taking

minerals in excess of RDA for performance.• Athletes who do not eat a balanced diet should

be advised to include a vitamin and mineral supplement.

• *

Calcium• Why is calcium so important?

• Normal bone health

• *

• Osteoporosis

• Who is at risk?

• Female athletes in aerobic running

• *

• Where do you find calcium?

• Dairy products

• *

• RDA for adolescent females is 1500mg/day

Water (H2O)

Water is necessary for human performance, as well as survival.• Necessary for cellular function• *• Necessary for elimination of waste products

Housed in 2 general locations: intracellular, extracellular

Water

• At rest, the water requirement for an adult is approx *• During exercise or high heat/humidity environments,

the daily consumption can increase to 5-10L• During exercise, a significant amount is lost to

metabolic heat• Sweat evaporation from the skin can easily result in an

hourly water loss of 2L or more for each hour of exercise

• What happens if you don’t replace the water you lost?

Dietary Habits of Athletes

• Eck’s study of 43 university football players indicated their diets were 34.7% CHO, 17% protein, and 42% fat.

• Recommended proportions are 45%–70% CHO, 12%–15% protein, and 20% fat.

• A high protein requirement as a prerequisite to athletic success is a myth.

Dietary Habits of Athletes

Conclusions• Many athletes do not consume proper

proportions of protein, CHO, and fat. • *• Athletes in sports that require lean bodies

tend to eat diets with insufficient calories.• *• Most athletes’ diets are deficient in

important minerals, i.e., calcium, iron, & zinc.

Diet and Wrestling Wrestlers often follow unhealthyweight loss procedures tocompete in lighter category.

• *

• Dehydration occurs through the use of laxatives and diuretics, fluid restriction, artificially induced sweating, and starvation.

• *

Wrestling (cont.)

Short-term effects of repeated bouts of extreme weight loss include:

• Increased blood viscosity.

• *• Kidney and liver

problems.• *.

Long-term effects may include interference with normal growth and development.

Wrestling Minimum Weight Project (WMWP)

Wisconsin instituted WMWP in 1989.• Weight loss must be no more than 3 lbs.

of weight loss/week. • *• Testing of athletes, along with nutrition

education for coaches, was done by trained volunteers.

WMWP (continued)

The NFSH has developed a national wrestling rule #1-3-1 that states:

“A medical professional should…establish a minimum (wrestling) weight through… checking body fat and hydration. The recommended minimum body fat should not be lower than 7%.”

What Can the Coach Do?

Coaches are an important source of nutrition information.

• People planning to enter the coaching profession should take at least one basic college nutrition course.

• Attend in-service meetings, professional conferences, or community education programs in sports nutrition.

• *

What Can the Coach Do? (cont.)

• Locate nutrition experts, including dietitians, university nutrition faculty, or sports medicine staff.

• Have athletes keep a record of their diet that is reviewed periodically by a person knowledgeable in nutrition.

• *

General Dietary Guidelines for Athletes

All sports nutrition programs should have 3 goals:

• Nutritional maintenance and development during training to ensure adequate recovery between training sessions

• *• Nutrition during competition

Nutrition During TrainingRecommendations include:

• 10% to 15% of calories from protein, 30% from fat, and the remainder from CHO.

• *• Little need for vitamin/mineral supplements

if diet is well balanced.• Using simple terms when educating young

athletes about nutrition.

MyPyramid, www.MyPyramid.gov

Pre-competition Diets• Avoid eating meals 2 to 3 hours before

event (digestion takes 2 to 3 hours to occur – foods eaten just before an event will do nothing for performance)

• *• Diet should consist of low-fat, easily

digestible foods• Liquid meals increase hydration and are

less likely to cause bloating or “heavy” feeling than solid meals.

• Foods should provide * grams of CHO or 3 to 5 grams/kg of body weight.

Nutrition During Competition

• The body has limited capacity for storing glycogen, and athletes may deplete those supplies before the event is over

• *• 2 hours can deplete the stores in

both the liver and muscle (“hitting the wall”)

• Most sports drinks provide CHO levels of *

Nutrition for Recovery

• Glycogen depletion can occur 2-3 hours after completion of exercise (80% of VO2 max)

• *• CHO intake of 0.5-0.7g/lb body mass during the first

30 minutes of recovery and again every 2 hours for 4-6 hours is adequate to replace glycogen stores

• *• www.scandpg.org

Weight vs. Fat Management

• Body weight consists of water, fat, and lean tissue.• *• When athlete fails to consume enough calories to

meet needs, fat is metabolized for energy.• Severe caloric restrictions (fasting) result in protein

breakdown (reduction of lean muscle mass = loss of performance.

• Most active females have a body fat *• Most active males have a body fat *

Minimal Competitive Weight

• Athletes should only weigh themselves once/week at the same time of day and after going to the bathroom.

• Males should have at least * of their total body composition in the form of fat.

• Females should have a minimum of * of their total body composition as fat.

• Determine body fat % by using skin calipers

Minimal Competitive Weight (MCW)

An athlete weighs 135 lbs and has 14% body fat.• Fat weight = 135 x .14 = 18.9 lbs• LBW = 135 – 18.9 = 116.1• MCW = 116.1 ÷ 0.95 = 122.2 lbs

• Fat weight = body weight x body fat %• LBW = total body weight – fat weight• MCW = LBW ÷ 0.95

Nutrition and Injury Recovery

Weight gain can occur with forced inactivity due to injury.

• Recommend cross training during recovery.• Runners can ride stationary bikes or run in

swimming pools.• Maintains aerobic fitness while burning

excess calories.• *

Supplements and Ergogenic Aids

• Supplements have become very popular with athletes of all calibers.

• Supplements can be divided into two categories: legal and illegal.

• Legal supplements: *, creatine, amino acids, and *.

• Illegal supplements: *, androstenedione, EPO, GHB, *.

Creatine• Creatine is found naturally in the cells

and is used to convert ADP into ATP (energy)

• Creatine has been found to be more helpful for athletes who use short bursts of energy than for endurance athletes.

• Produces an increase in energy at the cellular level which allows the athlete to train for longer periods of time.

• There are many published studies on creatine use that report conflicting results.

Quick Reference

• 1kg = 2.2 lbs• Protein requirements:

• 10-20% of total caloric intake• 0.8g/kg (normal)• 1.2-1.8g/kg (vigorous exercise)

• Carbohydrate requirements:• 60-70% of total caloric intake• 1g/kg (normal)• 5-7g/kg (vigorous exercise)

• Fat requirements:• No more than 30% of total caloric intake• 0.8g/kg