Nutrition in SportsNutrition in Sports

MAJ Michael R. Simpson, DOMAJ Michael R. Simpson, DOSports Medicine FellowSports Medicine Fellow

VCU- Fairfax Family PracticeVCU- Fairfax Family PracticeFebruary 2008February 2008

ObjectivesObjectives• Understand basic Understand basic

concepts of pre-race, concepts of pre-race, race, and post-race race, and post-race nutritionnutrition

• Discuss basic hydration Discuss basic hydration and prevention of and prevention of exertional hyponatremia exertional hyponatremia strategiesstrategies

• Be able to educate Be able to educate athletes about the facts athletes about the facts and fallacies of and fallacies of endurance sports endurance sports nutritionnutrition

Endurance Athlete QuestionsEndurance Athlete Questions

• Training and game day….should I and how do Training and game day….should I and how do I carbo load?I carbo load?

• What combo of carbs, fat, and protein is best What combo of carbs, fat, and protein is best prior to the race and long distance training?prior to the race and long distance training?

• During training and game dayDuring training and game day– Water or sports drink? How much do I need to Water or sports drink? How much do I need to

drink?drink?– Gels, carbs, or protein?Gels, carbs, or protein?– How many calories and how often?How many calories and how often?– Will caffeine help me perform better?Will caffeine help me perform better?

Endurance Athlete QuestionsEndurance Athlete Questions

• After the race or game:After the race or game:– What and how much should I drink?What and how much should I drink?– What should I eat?What should I eat?– When should I eat?When should I eat?

• Are there any proven legal sports Are there any proven legal sports supplements that I can use to improve my supplements that I can use to improve my performance?performance?

Keys to Endurance Keys to Endurance PerformancePerformance

• Maximize and maintain Maximize and maintain fuel (glycogen) suppliesfuel (glycogen) supplies

• Maintain and optimize Maintain and optimize hydration and electrolyte hydration and electrolyte balancebalance

• Prevent protein Prevent protein breakdown and maximize breakdown and maximize synthesissynthesis

• Efficient and timely Efficient and timely recovery from prior bout recovery from prior bout of exerciseof exercise

Let’s Talk CarbohydratesLet’s Talk Carbohydrates

• Carbos (CHO) converted Carbos (CHO) converted to glycogen and stored in to glycogen and stored in muscles and liver.muscles and liver.

• Glycogen is #1 fuel source Glycogen is #1 fuel source for endurance events of for endurance events of moderate to high intensitymoderate to high intensity

• Glycogen repletion is slow Glycogen repletion is slow and recovery time is and recovery time is directly related to ability directly related to ability to replenishto replenish

• Maintaining and restoring Maintaining and restoring glycogen is key to glycogen is key to performanceperformance

Let’s Talk CarbohydratesLet’s Talk Carbohydrates

• Carbo loadingCarbo loading– Old school: One week low Old school: One week low

carbs (deplete) with 1-3 day carbs (deplete) with 1-3 day high carbs priorhigh carbs prior

– New school: 3 days of high New school: 3 days of high carbo diet before race or carbo diet before race or long distance training sessionlong distance training session

– Events longer than 60-90 Events longer than 60-90 minutesminutes

• Goal: Pre-training/race Goal: Pre-training/race build up glycogen stores to build up glycogen stores to prevent “bonking” or prevent “bonking” or “hitting the wall”“hitting the wall”

Comparison of DietsComparison of Diets

• Low CHO diet (40% Low CHO diet (40% kcal from CHO)kcal from CHO)– Double Double

cheeseburgercheeseburger– Medium friesMedium fries– Chocolate milkshakeChocolate milkshake

• High CHO diet (70% High CHO diet (70% kcal from CHO)kcal from CHO)– 12 inch sub sandwich 12 inch sub sandwich

(lots of vegetables & (lots of vegetables & no mayo)no mayo)

– 500 ml apple juice500 ml apple juice– 250 ml chocolate milk250 ml chocolate milk– bananabanana

0

20

40

60

80

100

120

140

Day 1

Day 2

Day 3

Time

Mu

scle

Gly

cog

en

(mM

/kg

wet

wt)

High CHOLow CHO

Effects of Diet on Muscle Effects of Diet on Muscle Glycogen ContentGlycogen Content

Let’s Talk CarbohydratesLet’s Talk Carbohydrates(Training and Game/Race Day)(Training and Game/Race Day)

• Training and race day Training and race day diet should consist of:diet should consist of:– CHO: 55-70 % (6-10 CHO: 55-70 % (6-10

grams per kilogram of grams per kilogram of body weight body weight oror 8-10 8-10 kcals per kilogram)kcals per kilogram)

– Fats: 25-30% (no Fats: 25-30% (no benefit to extra)benefit to extra)

– Protein: 12-15% (1.0-1.5 Protein: 12-15% (1.0-1.5 grams per kilogram) of grams per kilogram) of high quality protein high quality protein

Carbohydrate SnacksCarbohydrate Snacks• Foods supplying Foods supplying 50 grams50 grams CHO CHO

– 500 ml juice500 ml juice– 3 medium pieces of fruit3 medium pieces of fruit– 1 honey sandwich1 honey sandwich– 2 breakfast bars2 breakfast bars– 1 sports bar (check label)1 sports bar (check label)– 1.3 bagels1.3 bagels– 1/2 cup dried fruit1/2 cup dried fruit– 1 cup white rice1 cup white rice– 1 baked potato1 baked potato

*average 70 kg endurance athlete should consume 560 *average 70 kg endurance athlete should consume 560 grams CHO per daygrams CHO per day

Sport BarsSport Bars

• Developed to provide an easily accessible Developed to provide an easily accessible source of CHOsource of CHO

• Many bars provide complex proteins and may Many bars provide complex proteins and may be high in fat. be high in fat. – Vary in type and amount of energy, CHO, protein and Vary in type and amount of energy, CHO, protein and

fat. fat. – Some provide only 150 kcal andSome provide only 150 kcal and

others up to 340 kcalothers up to 340 kcal– Many contain other agents, Many contain other agents,

herbs, etcherbs, etc– READ LABELS CLOSELY!READ LABELS CLOSELY!

*average sports bar provides about 40-60 *average sports bar provides about 40-60 grams of CHOgrams of CHO

Brands of Sports BarsBrands of Sports Bars

• Atkins Advantage BarAtkins Advantage Bar• Balance BarBalance Bar• Bioprotein BarBioprotein Bar• Clif BarClif Bar• Detour BarDetour Bar• Gatorade Energy BarGatorade Energy Bar• GeniSoyGeniSoy• Ironman Triathlon BarIronman Triathlon Bar• Low Carb Keto-BarLow Carb Keto-Bar• Luna BarLuna Bar• Metabolift BarMetabolift Bar

• Met-RxMet-Rx• PowerBarPowerBar• PremierNutrition BarPremierNutrition Bar• Protein Revolution Protein Revolution

Low Carb BarLow Carb Bar• Think DivineThink Divine• Tiger’s MilkTiger’s Milk• ZonePerfectZonePerfect• Sugar-Free Sugar-Free

ProteinPlusProteinPlus• Ultimate Low-Carb BarUltimate Low-Carb Bar

Sport GelsSport Gels

• Designed to deliver large amount of CHO Designed to deliver large amount of CHO in compact and easily consumed form in compact and easily consumed form

• Very slowly absorbed by body and must Very slowly absorbed by body and must have adequate amounts of water to have adequate amounts of water to dilute and lower osmolality dilute and lower osmolality   

• Gels may be effective source of energy, Gels may be effective source of energy, but challenge is taking in enough fluid. but challenge is taking in enough fluid.

• About 100 calories per package (25 About 100 calories per package (25 grams CHO)grams CHO)

Brands of Sport GelsBrands of Sport Gels

• e-Gele-Gel• GUGU• Power GelPower Gel• Clif ShotClif Shot• Hammer GelHammer Gel

Composition of Sport GelsComposition of Sport Gels

Crank Crank Sports e-GelSports e-Gel

82% Complex/82% Complex/18% Simple CHO18% Simple CHO

Amino acids, vitamin B6, Amino acids, vitamin B6, antioxidants, antioxidants,

GU GU Energy GelEnergy Gel

80% Maltodextrin/80% Maltodextrin/20% Fructose20% Fructose

Amino acids, herbal Amino acids, herbal blend, antioxidants, blend, antioxidants,

caffeinecaffeine

Power GelPower Gel Maltodextrin, Maltodextrin, fructose, dextrose fructose, dextrose

Amino acids, vitamins Amino acids, vitamins C/E, caffeine, kola nut, C/E, caffeine, kola nut,

ginsengginseng

Clif Shot Clif Shot Energy GelEnergy Gel

60% Complex/40% 60% Complex/40% Simple CHO from riceSimple CHO from rice

Magnesium, caffeine Magnesium, caffeine (some flavors)(some flavors)

Hammer GelHammer Gel 100% Maltodextrin100% Maltodextrin Caffeine (some flavors), Caffeine (some flavors), amino acidsamino acids

Glycemic Index and Glycemic Index and Insulin Response IndexInsulin Response Index

Glycemic Index (GI):Glycemic Index (GI): • Ranking of food based on blood glucose response Ranking of food based on blood glucose response

to reference foodto reference food– High GI (dextrose and maltose): Evoke large increases High GI (dextrose and maltose): Evoke large increases

in glucosein glucose• Carrots, raisins, corn flakes, breads, rice cakesCarrots, raisins, corn flakes, breads, rice cakes

– Low/Moderate GI (sucrose and lactose): Evoke Low/Moderate GI (sucrose and lactose): Evoke small/modest increases in glucose.small/modest increases in glucose.• i.e.. Yogurt, apples, dried fruit, lentils, beansi.e.. Yogurt, apples, dried fruit, lentils, beans

Insulin Response Index (IRI):Insulin Response Index (IRI): • Ranking of food based on blood insulin response Ranking of food based on blood insulin response

to same reference foodto same reference food

Glycemic Index of FoodsGlycemic Index of Foods

GI > 85GI > 85• White BagelWhite Bagel• English MuffinsEnglish Muffins• DoughnutDoughnut• RaisinsRaisins• Corn ChipsCorn Chips• Ice CreamIce Cream• Sports DrinksSports Drinks

GI < 60GI < 60• YogurtYogurt• Grapefruit/OrangesGrapefruit/Oranges• BeansBeans• PeanutsPeanuts• Apples/Pears/PlumsApples/Pears/Plums• MilkMilk• Brown RiceBrown Rice

Practical Use of GI and IRIPractical Use of GI and IRI

• Pre-race/trainingPre-race/training– Low to moderate Low to moderate

best to build up best to build up glycogen stores, glycogen stores, avoid glucose-avoid glucose-insulin spikes, GI insulin spikes, GI tolerabilitytolerability

• During raceDuring race– Moderate to high is Moderate to high is

best for sustained best for sustained energyenergy

Comparison of CHOs in Comparison of CHOs in Gel ProductsGel Products

• HoneyHoney• FructoseFructose• Power Power

Gel™Gel™• SucroseSucrose• DextroseDextrose• MaltodextriMaltodextri

nn

5

35

43

71

100

121

41

59

113

147

100

158

CHO GI IRI

Research funded by the National Honey BoardRichard Kreider, PhD

Concerns with Sport GelsConcerns with Sport Gels• High cost alternative High cost alternative • Some brands also contain Some brands also contain

other compoundsother compounds• Gastrointestinal Gastrointestinal

intoleranceintolerance• Should be used during Should be used during

training to assess training to assess tolerance for use during tolerance for use during racerace

• May lead to over May lead to over consumption/over-consumption/over-reliance on low-nutrient reliance on low-nutrient CHO sourcesCHO sources

Carbos During The Carbos During The Race/TrainingRace/Training

• Events lasting longer Events lasting longer than 60 minutesthan 60 minutes

• Ingest 30-60 grams Ingest 30-60 grams of CHO per hour (2 of CHO per hour (2 gel packs)gel packs)

• GI tolerableGI tolerable• With waterWith water• Prevent “bonking”Prevent “bonking”

Carbos After The Carbos After The Race/TrainingRace/Training

• Timing is everythingTiming is everything• To replenish glycogen stores To replenish glycogen stores

after exercise, 1.0 - 1.5 after exercise, 1.0 - 1.5 grams of CHO/kg body grams of CHO/kg body weight should be ingested weight should be ingested within 30 min and repeated within 30 min and repeated every 2 hr for 4 to 6 hr.every 2 hr for 4 to 6 hr.

• Add a little proteinAdd a little protein

Van Hall G et al. J Appl Physiol. 2000;88:1631-6.Van Hall G et al. J Appl Physiol. 2000;88:1631-6.

Recovery Time (hr)

Muscle Glycogen Resynthesis Muscle Glycogen Resynthesis RateRate

0

50

100

150

200

250

0 1.5 4

CHO/PROTEINCHO

WATER

Mu

scle

Gly

cog

en

(n

mo

l/kg

)

van Hall G et al. J Appl Physiol. 2000.

Carbo Summary For Your Carbo Summary For Your AthleteAthlete

• For long training runs and game For long training runs and game dayday– 60-70% CHO diet for 3 days prior, 60-70% CHO diet for 3 days prior,

and decrease the training loadand decrease the training load– Use low GI foodsUse low GI foods– Avoid high GI foods 1-3 hours before Avoid high GI foods 1-3 hours before

run/racerun/race• During run/raceDuring run/race

– Moderate to high GI sourceModerate to high GI source– 100 calories every 20-30 minutes for 100 calories every 20-30 minutes for

sessions longer than 60 minutessessions longer than 60 minutes• After run/raceAfter run/race

– Carbs within 30 minutes and Carbs within 30 minutes and continued for the rest of the day; continued for the rest of the day; some proteinsome protein

• Practice your nutrition; never try Practice your nutrition; never try something new on race day!something new on race day!

Protein Balance Bottom LineProtein Balance Bottom Line

• Positive protein/AA Positive protein/AA balance is balance is important in muscle important in muscle recoveryrecovery

• 4:1 carbo to protein 4:1 carbo to protein replacement after replacement after exercise probably exercise probably helpfulhelpful

• More research More research neededneeded

Hydration and Electrolyte Hydration and Electrolyte BalanceBalance

• WATER IS MOST WATER IS MOST ESSENTIAL NUTRIENTESSENTIAL NUTRIENT– 60% of body is water60% of body is water– 75% of skeletal muscle is 75% of skeletal muscle is

waterwater• Important functions of Important functions of

waterwater– Makes up plasma, which Makes up plasma, which

transports and delivers transports and delivers nutrients to tissuesnutrients to tissues

– Maintains body Maintains body temperature and pHtemperature and pH

– Maintains blood Maintains blood circulation circulation and pressureand pressure

– Supports energy Supports energy processesprocesses

Fluid BalanceFluid Balance

Dehydration and Dehydration and PerformancePerformance

Urine color test for dehydration

Lemonade—The good

Apple juice—The bad

Tea—The ugly

Monitoring HydrationMonitoring HydrationStatusStatus

1

2

3

4

5

6

7

8

9

Indices of HydrationIndices of Hydration

% Body % Body Weight Weight ChangeChange

Urine Urine ColorColor

Well Well HydratedHydrated -1 to +1% -1 to +1% 1 or 21 or 2

Minimal Minimal DehydrationDehydration -1 to -3%-1 to -3% 3 or 43 or 4

Significant Significant DehydrationDehydration -3 to -5%-3 to -5% 5 or 65 or 6

Serious Serious DehydrationDehydration > -5%> -5% > 6> 6

Establishing Fluid NeedsEstablishing Fluid Needs

• Estimate sweat rate or amount of Estimate sweat rate or amount of fluid lost in a specified period of time fluid lost in a specified period of time during defined exercise workloadduring defined exercise workload– A:A: Body weight: Pre - PostBody weight: Pre - Post– B:B: Fluid intake: Total volumeFluid intake: Total volume– C:C: Urine volumeUrine volume

• Sweat loss = A + B - CSweat loss = A + B - C• Sweat rate = Sweat loss/timeSweat rate = Sweat loss/time

Example of Fluid NeedsExample of Fluid Needs

• Body weightBody weight– Before = 70 kg and after = 67 kgBefore = 70 kg and after = 67 kg

• Fluid intake = 1.8 LFluid intake = 1.8 L• Urine volume = 0.7 LUrine volume = 0.7 L• Time = 2 hours or 120 min.Time = 2 hours or 120 min.• Sweat loss = (3 + 1.8 - 0.7) = 4.1Sweat loss = (3 + 1.8 - 0.7) = 4.1• Sweat rate = 4.1 L/2 hrs = 2.05 L/hrSweat rate = 4.1 L/2 hrs = 2.05 L/hr

Pre-Exercise Hydration Pre-Exercise Hydration Guidelines Guidelines

• Obtain body weight.Obtain body weight.• Check color of morning urine - pale Check color of morning urine - pale

color (1 - 3) indicates a good color (1 - 3) indicates a good hydration statushydration status

• Drink 16 to 20 fl oz of water or Drink 16 to 20 fl oz of water or sports beverage 2 to 3 hrs beforesports beverage 2 to 3 hrs before

• Drink 8 to 12 fl oz of water 0 to 10 Drink 8 to 12 fl oz of water 0 to 10 min before exercisemin before exercise

During Exercise During Exercise Hydration GuidelinesHydration Guidelines

• Drink 3-8 fl oz of water every 15-20 min Drink 3-8 fl oz of water every 15-20 min when exercising for < 60 minwhen exercising for < 60 min

• Drink 3-8 fl oz of a beverage with CHO Drink 3-8 fl oz of a beverage with CHO (5% to 8%) and sodium every 15-20 min (5% to 8%) and sodium every 15-20 min when exercisingwhen exercising> 60 min> 60 min

• DO NOT DRINK MORE THAN 1 L or 1 DO NOT DRINK MORE THAN 1 L or 1 Qt/hr during exerciseQt/hr during exercise

*One size does not fit all! *One size does not fit all!

Post-Exercise Hydration Post-Exercise Hydration Guidelines Guidelines

• Obtain body weight to estimate fluid Obtain body weight to estimate fluid losses and correct losses within 2 hrslosses and correct losses within 2 hrs

• Consume 1 liter of fluid for every liter lostConsume 1 liter of fluid for every liter lost• When re-hydrating rapidly, ingest 25% When re-hydrating rapidly, ingest 25%

more than sweat losses to assure optimal more than sweat losses to assure optimal hydration within 4 to 6 hrs after exercisehydration within 4 to 6 hrs after exercise

• Beverage should contain water to restore Beverage should contain water to restore hydration status, CHO to replenish hydration status, CHO to replenish glycogen stores, some protein, and glycogen stores, some protein, and sodium to accelerate re-hydration sodium to accelerate re-hydration

ACSM PositionACSM Position

• Thirst is not the Thirst is not the best hydration best hydration indicator for active indicator for active people and those people and those who are exposed to who are exposed to heatheat

• Athletes should Athletes should replace fluids in replace fluids in amounts that amounts that approximate sweat approximate sweat losses.losses.

Hydration Guidance For Your Hydration Guidance For Your RunnerRunner

• Monitor morning hydration Monitor morning hydration and pre-hydrateand pre-hydrate

• Estimate your sweat rate and Estimate your sweat rate and replace (600-1000 ml per replace (600-1000 ml per hour)hour)

• Never gain weight! Never gain weight! • Salty sweater….salt Salty sweater….salt

supplementsupplement• Sports drinks for > 60 minuteSports drinks for > 60 minute• Resist temptation to drink at Resist temptation to drink at

every water stopevery water stop• Thirst is a poor indicator of Thirst is a poor indicator of

hydration statushydration status

Endurance Event Performance Endurance Event Performance EnhancementEnhancement

• EPO = illegalEPO = illegal• RBC transfusion = RBC transfusion =

illegalillegal• Caffeine does Caffeine does

improve endurance improve endurance performance performance within legal limitswithin legal limits

• USADA: USADA: www.usantidoping.www.usantidoping.orgorg

SummarySummary

• Nutrition and hydration are key Nutrition and hydration are key elements to performanceelements to performance

• High carb diet with protein and some High carb diet with protein and some fatfat

• Timing is importantTiming is important• Sports drink versus waterSports drink versus water• Never gain weight and consider salt Never gain weight and consider salt

supplementsupplement• Practice your nutrition and Practice your nutrition and

hydration; never experiment on race hydration; never experiment on race day!day!

ReferencesReferences

1.1. American College of Sports Medicine: American Dietetic American College of Sports Medicine: American Dietetic Association and Dietitians of Canada: Joint position Association and Dietitians of Canada: Joint position statement nutrition and athletic performance. Med Sci statement nutrition and athletic performance. Med Sci Sports Exerc 2130-2138, 2000.Sports Exerc 2130-2138, 2000.

2.2. DiMarco NM, Samuels M: Nutritional considerations, in DiMarco NM, Samuels M: Nutritional considerations, in O’Connor FG, Wilder RP (eds): Textbook of Running O’Connor FG, Wilder RP (eds): Textbook of Running Medicine, New York, NY, McGraw Hill 2001, pp 469-Medicine, New York, NY, McGraw Hill 2001, pp 469-477.477.

3.3. Casa D.J.,  Armstrong L.E.,  Hillman S.K.,  National Casa D.J.,  Armstrong L.E.,  Hillman S.K.,  National Athletic Trainer's Association position statement: fluid Athletic Trainer's Association position statement: fluid replacement for athletes. J Athl Train (2000) 35 : pp 212-replacement for athletes. J Athl Train (2000) 35 : pp 212-224.  224.  

4.4. American College of Sports Medicine Position Stand: American College of Sports Medicine Position Stand: Exercise and Fluid Replacement. Med Sci Sports Exerc. Exercise and Fluid Replacement. Med Sci Sports Exerc. 377-389, 2007.377-389, 2007.