MedNut - Sports Nutrition PPT + Handout + Side Notes (untoshible)

8/15/2019 MedNut - Sports Nutrition PPT + Handout + Side Notes (untoshible)

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1

MEDICAL NUTRITION

SPORTS NUTR T ON

Dr. maria Lourdes Corazon-fernandez-tapang

15 october 2014

CONTENT

1.

Energy metabolism

2. Dietary requirements

3.

Nutrition: before, during, and after exercise

4.

Weight management

5. Dietary supplements and ergogenic aids

INTRODUCTION

Proper nutrition is a vital consideration for athletes who seek

to maximize their performance

A proper diet will provide proper nutrients and energy for

athletic performance, training and healing

Many factors affect nutrient needs and nutrient availability

including the athletes’ ― Physical condition

― Nutrient status

― Age

― Genetic background

These factors make it essential that the diet be individualized

SPORTS NUTRITION GOALS ARE TO ENSURE:

Adequate energy intake to meet the energy demands of

training

Adequate replenishment of muscle and liver glycogen with

dietary carbohydrates

Adequate protein intake for growth and repair of tissue,

particularly muscle

Adequate overall diet to maintain a healthy immune system

Adequate hydration

Consumption of food and beverages to delay fatigue during

training and competition

Minimization of dehydration during exercise

ENERGY METABOLISM

ENERGY CHO, fat, protein supply energy, with fats and CHO

being primary source

STORAGE energy is stored in the body in the of CP, CHO

(blood glucose, liver, muscle, glycogen), fat (serum

FFA and TG, muscle triglyceride, adipose tissue),

protein (muscle)TRANSFER two metabolic systems to transfer stored energy to

form ATP

ENERGY SYSTEMS

ANAEROBIC SYSTEM AEROBIC SYSTEM

These system are

capable of producing

ATP energy at a high

rate.

The main limitation of

this system is the

relatively small amount

of ATP that can be made

before fatigue ensues.

It supplies all of the

energy for low to

moderate intensity

exercise.

It supplies energy for

sleeping, resting, sitting,

walking and other forms

of low intensity physical

activity.

Anaerobic Metabolism

Phosphagen system

Glycolytic pathway

Aerobic Metabolism

Oxidative pathway

THE PHOSPHAGEN SYSTEM (ATP-CP SYSTEM)

Anaerobic

Adenosine Triphosphate and Creatine Phosphate provide

readily available energy present within the muscle

The amount of ATP in skeletal muscles is approximately

5 mmol/kg wet weight and is not sufficient to provide

continuous supply of energy

Creatine-phosphate is an ATP reserve in the muscle that can

be readily converted to sustain activity for 3-5 min.

Creatine-phosphate in skeletal muscle is approximately 4x

greater than ATP and is therefore the primary fuel for high

intensity, short-duration activities

Used for events lasting no longer than a few seconds and of

high intensity― Diving

― 100 m dash

― Weight lifting

― Fast break in basketball

― Jumping

THE ANAEROBIC GLYCOLYTIC PATHWAY (EMDEN-MEYERHOF-

PARNAS OR GLYCOGEN-LACTIC ACID SYSTEM)

Uses muscle glycogen and

glucose that are rapidly

metabolized anaerobically

through the glycolytic

cascade

This pathway supportsevents lasting 60 to 180

seconds

Approximately 25% to 35%

of total muscle glycogen

stores are used during a

single 30-second sprint or

resistance exercise bout.

― 200-m dash


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Neither the phosphagen nor the glycolytic pathway can sustain the

rapid provision of energy to allow muscles to contract at a very

high rate for events lasting greater than 2 to 3 minutes.

THE OXIDATIVE PATHWAY

The major substrates include muscle and liver glycogen,

intramuscular, blood, and adipose tissue triglycerides, and

negligible amounts of amino acids from muscle, blood, liver,

and the gut.

Can produce large amounts of ATP over time via the Kreb’s

cycle and the electron transport system. Fuels events lasting longer than 2-3 min.

Examples include

― 1,500-meter run

― Marathons

― Half-marathon

― endurance cycling or 500 meter swimming events.

The use of energy system over the other depends on:

duration of physical activity

intensity of physical activity frequency of exercise

type of physical activity

fitness level of the individual

nutrient intake and energy stores

ENERGY BALANCE

The objective of sports nutrition is to achieve energy balance,

which is achieved when energy expenditure equals energy

intake

ENERGY INTAKE ENERGY EXPENDITURE

Food

Fluids

Supplements

Basal Metabolic Rate

Thermic Effect of Food

Thermic Effect of Activity

Athletes need to consume adequate energy during periods of high-

intensity and/or long-duration training to:

LOW ENERGY INTAKES

Can result in:

― Loss of muscle mass

― Menstrual dysfunction

― Loss of or failure to gain bone density

― Increased risk of fatigue, injury, and illness

― Prolonged recovery process

DIETARY REQUIREMENTS

Athletes do not need a diet substantially different from that

recommended in the Dietary Guidelines for Americans andEating Well with Canada’s Food Guide

Cautions is recommended in using specific proportions as a

base for meal plans for athletes

BASIC NUTRIENTS

Nutrients are chemical substances in food that provide

energy, act as building blocks in forming new body

components, or assist in the functioning of various body

processes

CARBOHYDRATES

Carbohydrates is the optimal fuel for exercise

Yields approximately 4 kcals/gram

Carbohydrates are the basic source of energy for the body In general, carbohydrates (CHO) should always provide at

least 55% of total daily calorie (TDC) intake ideally 60-70% of

TDC

At meals, carbohydrates should take up 2/3 of your plate

Foods containing carbohydrates: bread, rice, pasta, cereals,

crackers, fruits, juices, vegetables, dried beans/peas, and

grains

The body converts sugars and starches to glucose for energy

or to glycogen for energy storage in the liver and muscles

― When glycogen stores are full, excess carbohydrates are

converted to fat

While a high-carbohydrate diet is essential to good health in

all individuals, it is especially important to the athlete

50-60% of the athlete’s caloric intake should be from

carbohydrates to keep the glycogen stores filled

Carbohydrate loading (during pre-competition meals) is used

to generate extra glycogen and requires a carbohydrate

intake of 70-80%

Athlete recommendation is 5-10 g/kg/day or

2.7 to 4.5 g/lb/day

― Endurance – 5-10 g/kg/day

― Strength – 5-7 g/kg/day

PROTEIN

Protein is critical to growth and development especially

muscle and bones

General functions of protein ― Function as enzymes to catalyse chemical reactions in the

body

― Many hormones are proteins

― Can be a source of energy

Yields approximately 4 kcals/gram

When carbohydrates and fats are not available (such

as in starvation) and during prolonged endurance

exercise

Used for building and repairing muscles, red blood cells, hair,

and other tissues

P h o s p h a g e n s y s t e m ATP-CP provides

rapid energy,anaerobic,seconds,produces 0.7ATP/PC

E M P p a t h w a y

Uses onlyglucose,anaerobic, highintensity activity1-3 min,produces 2ATP/glucose

O x i d a t i v e p a t h w a y

uses CHO, fat,protein, aerobic,longer periods,produces 38ATP/glucose

•Body weight and healthMAINTAIN

•Training effectMAXIMIZE


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Used for energy when carbohydrates are not available

Proteins are derived from animal foods – meat, milk, eggs,

fish, cheese, and poultry. Also, from soybeans, dry beans,

some nuts, and whole-grain products.

As stated earlier, proteins may be used by the body for

cellular energy, but proteins are the body’s least efficient

source of energy.

Recommended protein intakes can generally be met through

diet alone, without the use of protein or amino acid

supplements

Extra protein not needed by the body, is burned for energy orstored as fat

― The body cannot store protein

Protein intake should be approximately 10-12% of caloric

intake

The Dietary Reference Intake (DRI) for adults is 0.8 g/kg body

weight

Athlete recommendation is 1.2-1.7 g/kg or

0.5 to 0.8 g/lb/day

― Endurance athletes

1.2 – 1.4 g/kg (1.2-1.5 g/kg)

― Strength athletes

1.6 – 1.7 g/kg (1.5-1.7 g/kg)

FAT

Source of energy, fat-soluble vitamins, and essential fatty

acids

Yields 9 kcals/g (over twice carbohydrates and proteins)

General functions of fat

― They carry vitamins A and D to cells, and are necessary for

normal growth and development

― Fats insulate the body

― They protect the body from the impact of injuries, and

shield the body’s organs

― Add flavor to our food

Helps sustain prolonged exercise

Source of stored energy, burned mostly during low-level

activity, and when other sources are not available Main sources include meats, eggs, milk, cheese, fried foods,

butter, margarine, salad dressings, oils, and mayonnaise

Healthier fat choices: nuts, seeds, olive oil, canola oil, fish,

avocados, and olives

Fats are necessary and important in our diet. Yet many

people consider fats to be a harmful nutrient

― The problem is the fact that we often eat far more than

the daily recommended amount of fats (30% of our

caloric intake)

High-fat diets are associated with heart disease,

hypertension, and cancers

Fats are not digested as quickly as other nutrients

Fats are used when carbohydrate sources are depleted

High-fat diets are not recommended for athletes Athele recommendation is 1.0-2.0 g/kg/day

CHO 5-10 g/kg/day or 2.7 to 4.5 g/lb/day

CHON 1.2-1.7 g/kg or 0.5 to 0.8 g/lb/day

FAT 1.0-2.0 g/kg/day

VITAMINS AND MINERALS

Vitamins do not provide energy!

Vitamins are essential for maintaining good health

Needed to regulate processes in the body

― Used to utilize energy from carbohydrates, protein, and

fat

A lack of vitamins in the diet leads to deficiency conditions,

which express themselves in a variety of ways

Most vitamins cannot be synthesized by the body and must

be ingested via foods or pills

No single food or food group will supply all the vitamins

needed by the body

― A good reason to eat a variety of different foods

Vitamins are usually identified as either fat soluble or water

soluble

― Fat soluble vitamins (vitamins A, D, E, and K) are

emulsified and absorbed in the small intestines

These vitamins are stored in body cells. Especially

liver cells

― Water soluble vitamins (B complex and vitamin C) are

absorbed along with water through the digestive tract

and dissolved in body fluids

The body doesn’t store these vitamins well and

excess quantities are excreted in urine

Vitamin requirements do not increase during exercise

―

Available evidence does not justify supplementing thediet of the athlete with vitamins to improve physical

performance unless a pre-existing vitamin deficiency

exists

― Likewise, in athletes who do not choose nutrient dense

foods, supplementation may be suggested

Vitamins and minerals found to be of concern in athletes

diets:

― Calcium

― Vitamin D

― B Vitamins

― Iron

― Zinc

― Magnesium

―

Antioxidants such as Vitamin C, E, beta-carotene, andselenium

B Vitamins

Two major functions related to exercise:

― Involved in energy production

Thiamine, riboflavin, niacin, pyridoxine, pantothenic

acid, and biotin

― Required for production of red blood cells, protein

synthesis, and in tissue repair and maintenance including

the CNS

Vitamin B12 and folate

Vitamin D

For adequate calcium absorption and bone health Regulates development and homeostasis of the nervous

system and skeletal muscle

Athletes who train indoors

Recommended daily intake:

― 5 µg/day or 200 IU (19-49 y/o)

Antioxidants: Vitamin C and E, β-carotene, and Selenium

Because exercise can increase oxygen consumption, it has

been hypothesized that long-term exercise produces a

constant oxidative stress on muscles and other cells

Habitual exercise however has been shown to result in an

augmented antioxidant system

Should not exceed tolerable upper intake levels Vitamin C is also needed for absorption of iron

MINERALS: Calcium, Iron, and Phosphorus

Minerals do not provide energy!

Minerals are inorganic substances and are known to have

functions essential to life

Calcium

― Bone health, bone strength, muscle contraction, nerve

conduction, and normal blood clotting

― Athletes need 1200-1500 mg of calcium per day

One serving from the dairy group has about 300 mg

calcium

Iron – one of the most prevalent nutrient deficiencies

observed among athletes ― Oxygen carrying proteins, haemoglobin and myoglobin

― Enzymes involve in energy production

― Women need 15 mg and men need 10 mg of iron each

day

Phosphorus

― For bone health

― Needed for strong bones and teeth

Sodium, Potassium, and Chloride

― Particularly for athletes who sweat profusely


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― Sodium, potassium, and chloride are important for

maintaining normal fluid balance in the body as well as in

generation of muscle impulses

― Potassium – regulates cardiac rhythm

― Sodium loss in sweat outweighs potassium and chloride

loss

― Loss of this electrolytes will cause cramping

Exercise does not seem to affect dietary needs of most

minerals with the exception of the effects of sweating

― Heavy sweating may lead to excess losses of sodium,

chloride, and potassium ― Losses of these minerals may affect performance

― It is recommended that athletes involved in prolonged

activity, especially those who are considered “salty

sweaters” consume more salt in their meals before and

after activity

Generally, this added salt can easily be gained

through the salt added to foods and not through “salt

pills”

WATER

Water is often considered the most important nutrient

― Failure to consume other nutrients will show harmful

effects on the body after several weeks or months but

humans can only survive without water for a few days! General function of water

― Provides an aqueous medium for chemical reactions to

occur and for transportation of its products

― Provides a medium for transportation of oxygen,

hormones, nutrients, etc. throughout the body (i.e. the

blood)

― Facilitates thermoregulation for the body (i.e. sweat)

― Lubricates joints and cushions organs and tissues

― In saliva and gastric secretions, water helps digest food

Note that a loss of fluid through exercise may have an effect

on these functions; many of which will affect performance

Dehydration – loss of >2% body weight

Compromise aerobic performance and may impair

mental/cognitive performance – heat stress

We don’t rely on thirst mechanism but depends on a timely

basis in rehydration (we hydrate even not thirsty)

FLUID REPLACEMENT

Exercise increases water loss

― During normal breathing, water is added to inspired air to

protect delicate respiratory cells from drying out

Increased breathing during exercise increase this loss

― Heat production is a byproduct of muscle contraction

Increased muscle contraction during exercise

increases overall body heat forcing the body to

compensate through sweating

Athletes may lose up to 1 liter per hour

Water loss affects performance

― Diminished water content in the blood causes:

Diminished capacity to transport oxygen and

nutrients to body cells

Diminished capacity to get rid of excess heat from

working muscles causing increased body temperature

o Body cells must have a consistent temperature

to function properly (homeostasis)

― Loss of fluid causes cells to shrink (crenation) which

affects their normal function

Hydration Protocol

2 hours

before

15 min

before

Every 15 min

during

After activity

2-3 cups 1-2 cups ½ - 1 cup

At least 2

cups for each

pound of

body weight

lose

SPORTS DRINK

Help replenish lost sodium and glycogen stores

― During heavy sweating, water is not the only element lost

― Electrolytes such as sodium, potassium, chloride, and

traces of some others are also lost

Of these, sodium is lost in the greatest abundance

During exercise of 2 hours or less the body is able to reabsorb

sodium loss

― During exercise lasting less than two hours, the athlete

would need to pay more attention to fluid replacement to

address water loss through sweating than to sodium

replacement

― Water works well as a fluid replacement beverage under

these conditions During exercise lasting over 2 hours and in hot environments,

sodium loss in sweat occurs too rapidly for reabsorption to

occur and may also significantly decrease glycogen stores

(stored glucose)

― Sports drinks may be a good option for fluid replacement

during exercise lasting over 2 hours and for exercising in

the heat

Sports drinks may help to replenish lost sodium and

glycogen stores

Sodium replacement and maintaining hydration

during exercise may help to reduce muscle cramping

during exercise especially in salty and heavy sweaters

o One cause of muscle cramping is an electrolyte

imbalance caused from fluid and sodium lossfrom sweating

o It should be noted that another cause of muscle

cramping is muscle fatigue

There are many types of sports drinks to choose from and

choosing one over another is up to each individual

― However, there is a proper proportion of the chemicals in

the drink in order to optimize performance and limit any

detrimental effects

Guidelines in choosing sports drink

― 6-8% carbohydrates is recommended

Less likely to induce gastric distress

o Due to slowed gastric emptying in most

individuals

Water absorption is maximized ― Sodium content of 460-690 mg/L

Replace loss

Encourage drinking

o Since sodium tends to induce thirst

Cold drink is preferable because it attenuates changes in core

temperature and peripheral blood flow, decreases sweat

rate, and speeds up gastric emptying time

Example of a sports drink recipe

― 1 quart or 1 liter water

― 1/3 cup sugar

― ¼ teaspoon table salt

― Flavor to taste – use orange juice, lemon juice, etc.

― Keep refrigerated

Monitoring hydration status

The body’s thirst mechanism lags behind dehydration

― By the time you are thirsty, you are already dehydrated

― Therefore, thirst is not a good indicator of hydration

There are a number of very expensive and time consuming

test to monitor hydration but this process can be

accomplished with relative ease

― Urine color is a good indicator of hydration

Diet, supplementation, or medications, may affect

urine color

― Weight loss that occurs during a single bout of exercise is

likely due to fluid loss

Changes in body weight can be used as a marker forshort term fluid loss

One liter of water weighs approximately 1 kg (2.2 lbs)

o If an athlete completes a hard workout lasting

approximately one hour and loses 2 kg of body

weight it can be assumed that approximately 2

liters of fluid have been lost

o Or just simply drink until the pre-workout weight

is reached


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Fluid replacement strategies

Pre-hydration should begin at least 4 hours before

competition

― Recommended is 5-7 mL/kg (5-10 mL/kg or 2-3 mL/lb)

Ex: a 50 kg (110 lb) female would drink 250-350 mL

(8-12 oz or 1-1 ½ cups)

― This recommendation assumes the athlete is in a

hydrated state at the time

― It should be noted that water is sufficient, however,

sodium stimulates thirst and retention of body water so a

beverage that contains sodium may be beneficial ― Pre-hydration should be determined on an individual

basis and by trial and error to determine the appropriate

amount for each individual

Too little may lead to dehydration during competition

and therefore, decreased performance

Too much may leave the athlete feeling bloated and

cause too frequent urine brakes that may interfere

with pregame activities

Hydration during activity

― it is generally recommended that an athlete drink 6-12 oz

of fluid every 15-20 minutes

Small amounts taken frequently are tolerated best by

most athletes and leads to more effective gastric

emptying Hydration needs during activity is highly individual

and routines should be established well before

competition to avoid introducing a “new” routine

during competition

― Cool beverages are tolerated best although studies do not

show that temperature influences gastric emptying

Free access to water before, during, and after activity should

be encouraged

Before Exercise During Exercise After Exercise

At least 4 hours

before

5-7 ml/kg body

weight (2-3

ml/lb)

To avert

dehydration

Dependent on

sweat rate,

exercise

duration, and

opportunities to

drink

6-12 oz every

15-20 min. (not

more than 1

cup)

Recovery from

dehydration

16-24 oz (450-

675 ml) of fluid

for every pound

of body weight

lost

HYPONATREMIA

A potentially serious medical complication that may occur in

endurance athletes during prolonged exercise such asultramarathons or triathlons

― Events lasting 4 hours or more and is more common in

heat and high humidity

Occurs when plasma sodium concentration falls below

normal (130 mEq/L)

Sodium plays a vital role in maintaining normal fluid balance

throughout the body

― Low sodium level in the extracellular compartment

causes fluid to move into cells causing them to swell

― This is particularly important in nerve cells which require

sodium in proper proportions in order for nerve

conduction to occur

Causes:

―

Excessive sodium loss due to heavy sweating ― Overconsumption of hypotonic fluids (water)

Signs and symptoms:

― Dizziness, confusion, lethargy, seizure, loss of

consciousness or coma, and death

Prevention: for events lasting over 3 hours replace sodium

loss through use of fluids containing sodium or eating salty

foods

― Matching amount of sweat lost

Athletes should be encouraged to consume enough

fluid to match fluid loss and prevent dehydration

while not exceeding the amount of fluid lost

― Replacing sodium loss – 0.5 to 0.7 g/L

NUTRITION BEFORE, DURING, AND AFTER EXERCISE

PRE-EXERCISE OR PRE-GAME MEAL

Purpose:

― To help prevent hypoglycaemia

Symptoms: light-headedness, needless fatigue,blurred vision, and indecisiveness – all of which can

interfere with performance

― To help settle the stomach absorb some of the gastric

juices, and decrease hunger

― To fuel muscles, both with food eaten in advance that is

stored as glycogen, and with food eaten within an hour

― To pacify the mind with the knowledge that the body is

well fuelled

Characteristics of a Pre-game Meal

Meal or snack should provide sufficient fluid to maintain

hydration

↓ fat and fiber to facilitate gastric emptying and minimize

gastrointestinal distress ↑ carbohydrate to maximize maintenance of blood glucose

Moderate in protein

Composed of familiar foods

Well tolerated by the athlete

Sports nutrition for performance benefits must begin day in

advance

― Every day, eat adequate high-carbohydrate meals to fuel

and refuel your muscles so they will be ready for action

Food eaten within an hour before exercise primarily

decreases hunger and maintains blood sugar

o It doesn’t signif icantly replenish muscle glycogen

stores

When exercising for more than 1 hour (60-90 mins.),

carbohydrates which slowly enter the bloodstream as they

are digested (low glycemic index) such as rice, pasta, yoghut,

oatmeal, bean soup, lentils, apples, or bananas are ideal

― When eaten an hour before exercise, these slow

carbohydrates will be digested enough to be burned for

fuel, and then will continue to provide sustained energy

during long workout

When exercising for less than an hour, snacking on any tried-

and-tested foods that digest easily and settle comfortably is

satisfactory.

― Bread, English muffins, bagels, crackers, and pasta are a

few of the most popular high-carb, low-fat choices

Limit high-fat proteins like cheese, streak, hamburgers, and

peanut butter ― they take longer to empty from the stomach because the

fat delays gastric emptying

― may cause sluggishness and nausea

Be cautious with sugary foods (such as soft drinks, jelly beans,

and even lots of maple syrup or sports drinks) or

carbohydrates that quickly enter the bloodstream as they are

digested (potato, honey, or corn flakes) – postprandial

hypoglycaemia

― Many athletes who eat these foods within 15-120

minutes before hard exercise can experience a drop in

blood sugar that leaves them feeling tired, light-headed,

and needlessly fatigued

― Experiment and learn how your body responds

Allow adequate time for food to digest ― Remember that high calorie meals take longer to leave

the stomach than do lighter snacks

― The general rule of thumb is to allow at least 3-4 hours

for a large meal to digest, 2-3 hours for a smaller meal, 1-

2 hours for a blended or liquid meal, and less than an

hour for a small snack, according to your own tolerance

― Some athletes can comfortable eat before they exercise,

but others prefer to abstain. Both sports perform well,

and both have simply learned how to best fuel their

bodies


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― It should be noted that exercise increases blood flow to

working muscles and away from digestive organs

This can cause stomach irritation if a large meal is

eaten just prior to exercise

Always eat familiar foods before a completion

― Don’t try anything new!

― New foods always carry the risk of settling poorly; causing

intestinal discomfort, acid stomach, heartburn, or cramps

Drink plenty of fluids

Carbohydrate Loading The purpose of carbohydrates loading is to “super-

compensate” for glycogen depletion in an effort to store the

maximum amount of glycogen possible prior to an event

Athletes who may benefit from the strategy:

― Endurance athletes whose events last for more than 90

minutes

Examples: long-distance runners, swimmers,

bicyclists, and cross-country skiers

― Athletes involved in sports that require prolonged

movement of varying intensities

Examples: soccer, lacrosse, and ice hockey

― Athletes who participate in tournament sports such as

tennis

The most accepted protocol is a 6 day cycle ― Phase 1 – “depletion phase”

The athlete participates in 3 days of high intensity

training to deplete glycogen stores

o The first day should be 90 minutes of intense

training

o Followed by 2 days of 40 minutes of intense

training

Carbohydrate intake during this phase should be

5 g/kg/day – the minimum amount recommended to

athletes in training

― Phase 2 – “repletion phase”

Intensity of training is tapered over the next 3 days

Carbohydrate intake increases to 10 g/kg/day

This is followed by 1 day of rest

Some side effects may occur

― During, carbo-loading, the athlete’s weight should

increase by 1-3 pounds, since water is stored with

glycogen

This may not be tolerated well by some athletes who

may feel sluggish and heavy

― Eating too many carbohydrates can lead to intestinal

distress

Choose wholesome, fiber-rich carbohydrates

― to keep your system running smoothly

― pasta, rice, bran muffins, whole wheat bread, cran

cereals, fruits, and vegetables are good choices

DURING EXERCISE

Important for endurance events lasting longer than an hour

when an athlete has not consumed adequate food or fluid

before exercise, or if an athlete is exercising in an extreme

environment (e.g. heat, cold, or high altitude)

Rationale:

― replace fluid losses

― provide carbohydrates for maintenance of blood glucose

levels

― provide needed sodium lost during heavy sweating

Recommended intake:

― Events lasting more than one hour or less: 6-8% CHO in

sports drink

―

Events longer than one hour: 0.7g CHO/kg bodyweight/hr or 30 to 60 g per hour

― Sodium: 0.5 – 0.7 g/L of fluid lost

― Fluid as much as sweat rate or approximately 1 cup every

15-20 min.

POST-EXERCISE/RECOVERY MEAL

What you eat after a hard workout or competition does affect

your recovery

Foods eaten after exercise or competition require the same

careful selections as the meal before exercise

Competitive athletes who are engaged in2 or more workouts

per day must be especially concerned about recovery diet

such as:

― Football player at training camp

― Competitive swimmers who compete in multiple events

per meet

― Triathletes who train twice per day

― Aerobics instructors who teaches several classes daily

― Basketball players who needs to endure the entire season

of intense training and competing

Athletes commonly have reasons to eat inadequately afterexercise, including that they don’t feel hungry and don’t have

time

Provide adequate fluids, electrolytes, energy, and

carbohydrates

― Replace muscle glycogen and ensure rapid recovery

RECOVERY CARBOHYDRATE:

― 1.0 to 1.5 g/kg (0.5-0.7 g/lb) body weight

(0.75-1.5 g/kg body weight in the handout)

Ex: a 176 lb athletes should consume approximately

120 g of carbohydrates

o This could easily be achieved with a banana, 10

oz of sports drink, and a bagel

o

Consumption of carbohydrates in smaller, more

frequent meals appears to further aid the rate atwhich muscle glycogen is replaced in the hours

after exercise

- With larger meals, blood glucose and insulin

rise rapidly and then return to baseline

relatively quickly

- Blood glucose levels can be sustained for a

longer period of time with smaller meals

― Ideally, carbohydrate-rich foods and beverages should be

consumed within 1st 30 minutes (15-30 minutes in the

handout) after a workout and again every 2 hours for 4

to 6 hours

This is when the enzymes responsible for making

glycogen are most active and will mostly rapidly

replace the depleted glycogen stores ― Liquids and solid foods will refuel muscles equally well

― Glucose rather than fructose is the preferred substrate

Studies show fructose does not result in glycogen

synthesis rates that are as high as those with glucose

― Solid foods should have a high glycemic index (causes a

rapid rise in blood glucose levels)

These are most effective in enhancing the resynthesis

of glycogen

Ex: white bread, corn flakes, baked potatoes, white

rice, pancakes, bagels

Many “energy bards” have a high glycemic index

RECOVERY PROTEIN:

― Protein intake after exercise is important for muscle

anabolism

Provide amino acids for building and repair of muscle

tissue

― 6 g immediately after exercise (0.1 g/kg body weight)

― Good examples of proteins are:

Yogurt with fruit in the bottom

Chocolate milk

Turkey sandwich

― Some protein can actually enhance glycogen replacement

in the initial hours after hard exercise

― Protein eaten along with carbohydrates is recommended

RECOVERY ELECTROLYTES

― Sweating not only causes water loss but also some

minerals (electrolytes) such as potassium and sodium that

help the body function normally

― Electrolytes losses are primarily responsible for muscle

cramping and intolerance to heat

― Most athletes should be able to consume more than

enough electrolytes from standard post-exercise foods

Salt tablets or special supplements are rarely needed


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WEIGHT MANAGEMENT

BODY COMPOSITION

Refers to all of the components that make up the body

Divided into 2 main categories:

― Fat mass

― Fat-free or lean body mass

Includes muscle, bone, fluids, and organs

― Most athletes are interested in the ratio of fat mass to

total body mass which is commonly expressed as percent

body fat Essential fat is the minimum amount of fat necessary for

proper physiological function

Description Women Men

Essential fat 10-13 % 2-5 %

Athletes 14-18 % 6-11 %

Fitness 19-23 % 12-16%

Average 24-29 % 17-23 %

Obese 36 % 29+ %

―

Essential fat for males = 3% of body weight

― Essential fat for females = 12% of body weight

Of this 12% approximately 9% is considered sex-

specific fat

o this is fat needed for proper hormonal and

reproductive functions

― Body composition that drops below these levels

interferes with normal body function

Body Fat norms are as follows

Females Males

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Three levels of assessment techniques are used to assess

body composition:

― LEVEL I – DIRECT ASSESSMENT

Based on analysis of cadavers

Not used in clinical practice

― LEVEL II – INDIRECT ASSESSMENTS

Hydrostatic (underwater: weighing)

o Traditionally considered as the most accurate

method

o The subject exhales and is weighed while

submerged in a tank of water o Measures body density which is then translated

mathematically into percent body fat

Plethysmography (Bod Pod)

o Measures displacement of air to determine body

volume

o Once body volume is determined, body density

can be calculated and body fat estimated

o The subject sits in an air-tight enclosure while

amount of air displaced is sensed by a special

diaphragm and pressure transducer

o May underestimate body fat by 2-3%

Dual X-ray Absorptiometry (DXA)

o Originally developed to assess bone mineral

o Fairly accurate, quick and non-invasive

o Cost and accessibility limits its use in practice

― LEVEL III – DOUBLY INDIRECT ASSESSMENT

Skinfold Calipers

o Makes use of large “pinchers” that measure

thickness of the fat layer on specific body sites –

abdomen, biceps, triceps, subscapula,

supraspinale, medial calf, and front thigh o Method of choice because of its convenience

and because its relatively inexpensive

Bioelectrical impedance analysis (BIA)

o An imperceptible electrical current is sent

through the body which flows up one leg and

down the other

o Based on the principle that an electrical signal is

more easily conducted through lean tissue than

fat or bone

o Fat mass is estimated by subtracting the BIA-

determined estimate of FFM from total body

mass

o Hydration status affects result

All methods for body fat measurement have potential errors

WEIGHT GAIN STRATEGIES

Weight gain should be achieved through a gradual increase in

energy intake

Theoretically, in order to gain 1 pound of body weight per

week, the consumption of an additional 500 calories per day

is needed

― The extra calories should primarily come from extra

carbohydrates

Carbohydrates fuel muscle so the muscles can

perform intense muscle-building exercise ― Energy coming from fat should not exceed more than

30%

Increased protein intake is likewise recommended

― Daily increase of 14 grams per day

― To provide necessary amino acids for muscle growth

To date, research indicates that protein powders and amino

acid supplements are a fruitless expense when it comes to

gaining muscle weight

― The only reason some athletes may see results from

these is likely due to the additional calories

Weight is most likely gained if larger-than-normal meals are

consumed

Finding the time to eat can be the biggest challenge to

boosting caloric intake

― Pack portable snacks

― Eat frequently throughout the day

― Eat larger than normal portions at mealtime

― Eat higher calorie foods

Taking the prescribed 500-1000 additional calories per day

should cause some weight gain

― It is vital to include muscle-building resistance exercise

(weight workouts) to promote muscular growth rather

than just fat deposits


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― It is recommended to have body fat routinely measured,

to be sure that weight gain is mostly muscle, not fat

WEIGHT LOSS STRATEGIES

Understanding body composition is an important component

of weight loss

― Muscle weighs more than fat

When an individual begins an exercise program in an

effort to lose weight he or she may find that the scale

is not showing significant weight loss – however, it is

likely that body composition is changing (fat may bedecreasing while muscle is increasing)

― For this reason some form of body composition analysis

should be utilized rather that body weight itself

Body fat is stored energy

― In order to decrease body fat, one must burn more

calories that he or she eats which forces the body to use

these energy stores (fat) – eat less and exercise more

― It should be noted that every human body is different and

fat is stored at different rates for each person

Storing fat can be affected by genetics, health, etc

Theoretically, 1 lb per week should be lost if 500 fewer

calories per day is eaten

― It is recommended that only 1-2 pounds per week be lost

for safety reasons To lost weight healthfully, and successfully keep it off pay

attention to dietary habits

― Pay attention to the quantity of food eaten

― Pay attention to when food is eaten (eat big breakfasts,

rather than big dinners)

― Pay attention to why food is eaten

i.e. boredom, stress loneliness, or actually hungry

― Studies show that eating 5-6 small meals per day is an

effective method to loose body fat

Eat slowly – the brain needs about 20 minutes to receive the

signal that food has been eaten

― No matter how much food is consumed during those 20

minutes, the satiety signal doesn’t move any faster

Exercise regularly but not overdo it

― Moderate intensity – can be sustained longer and to

ensure fats are mobilized and not carbohydrates

― Too much exercise may lead to injury, fatigue, and

irritability

― Exercise will be more satisfying when it is for fun and

fitness, not for simply burning off calories

Crash diets never work

― Weight loss fads are common in today’s world

― These technique usually focus on restriction of calorie

intake and usually have an individual eating foods that

vary from their usual choices

― Such diets are unsuccessful because losing body fat and

keeping it off requires a behaviour change that can

continue throughout the person’s life!

― These diets can actually cause long term weight gain

because caloric restriction causes the body to slow its

metabolism in an effort to save the calories that are

available

This means that the body will burn less calories day to

day than normal

― These fads are dangerous and can cause problems such

as hair loss, weakened immune system, pH imbalances,

and sudden death

Weight loss should be done only during off season

RAPID WEIGHT LOSS IN SPORTS

Some sports dictate that athletes make changes in bodyweight and composition that may not be best for the

individual athlete

― Sports that have weight categories because differences in

body size make it impossible for all athletes to fairly

compete among one another

Examples include wrestling, boxing, martial arts, and

lightweight rowing

― Body-conscious sports where physical appearance may be

judged

Examples include gymnastics, figure skating, horse

racing, and cheerleading

With extreme energy restrictions, losses of both muscle and

fat mass may adversely influence an athlete’s performance

Weight loss tactics include calorie restrictions, excessive

exercise, fluid restriction, or a combination (exercising in

rubber suits, spitting in a cup, etc)

These tactics have serious risks and should never be

condoned

― Most health risks are associated with prolonged energy

deprivation or dehydration ― There are several documented cases of deaths due to

these tactics

― Other side effects include frequent nose bleeds,

headache, dizziness, nausea, etc

― Studies are also showing that the weight “cycling” of

these athletes is leading to lowered metabolic rate as

aging occurs and an increase likelihood of being

overweight later on in life

― Many states are implementing rules to limit such tactics

in order to create a safer environment for the athletes

In 2006 the National Federation of State High School

Associations instituted rule changes that include:

o A body fat assessment no lower than 7% in

males and 12% in females o A monitored weight-loss program that does not

exceed 1.5% loss of body weight per week

o A specific gravity of urine not to exceed 1.025

ERGOGENIC AIDS

Any substance (or food) that is believed to enhance one’s

performance above normal standards.

The IOC definition: “The administration or use of substances

in any form alien to the body or of physiological substances in

abnormal amounts and with abnormal methods by health

persons with the exclusive aim of attaining an artificial and

unfair increase in performance in sports.”

The use of these substances and practices is controversial.

There is great concern about the number of athletes engaging

in the use of ergogenic aids.

― Drug testing has been instituted in many sporting

programs in order to help curtail the use of these

substances

Because of ethical violations associated that can result, use of

these substances cannot be condoned!

COMMON ERGOGENIC AIDS

Ergogenic aids that perform as claimedErgogenic aid Pros* Cons Remarks

Creatine Widely used.

Build muscleand enhance

recovery.

Effective in high

intensity activity

in sports.

Not for

endurance

sports such as

distance

running.

The effects of long-

term use of creatineremain unknown.

Screening of liver

or kidneydysfunction.

Caffeine Central nervous

system

stimulant.

Diuretic.

Anxiety.

Rapid heartbeat.

Gastrointestinal

distress

Athlete should

drink a lot of

fluid.

Sodium

Bicarbonate

Effective as a

blood buffer

(role in acid-

base balance

and prevention

of fatigue).

Diarrhea.

Protein and

Amino Acid

Supplements

Protein and amino acid supplements are no more or no less

effective than food when energy is adequate for gaining lean

body mass.


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MedNut - Sports Nutrition PPT + Handout + Side Notes (untoshible)

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Transcript of MedNut - Sports Nutrition PPT + Handout + Side Notes (untoshible)