Embed Size (px)
DESCRIPTION
The importance of Carbohydrates explained.
Citation preview
Carbohydrates in Exercise and Recovery
Rookie version
Outline
I. Carbohydrates: Defini7ons, diges7on, absorp7on A. Carbohydrates in the diet B. Diges7on and absorp7on of carbohydrates C. Carbohydrate metabolism D. Glycogen—storage of carbohydrates in the body
II. Proper7es of carbohydrates: Considera7ons for sports performance
A. Glycemic index B. Glycemic load C. High-‐fructose corn syrup
III. Training A. Carbohydrates before exercise B. Carbohydrates during exercise C. Recovery D. Meal planning
IV. Compe77on
A. Carbohydrate loading B. Pre-‐compe77on meals C. Carbohydrates during compe77on
I. Carbohydrates:
Defini7ons, Diges7on, Absorp7on, and Storage
Carbohydrates in Sports Nutri=on § Carbohydrates (CHOs) are a major fuel source for exercising muscle, especially in high-‐intensity or long-‐dura7on ac7vi7es
§ Carbohydrates can influence fluid absorp7on from the intes7ne (hydra7on)
§ Some CHOs can cause gastrointes7nal intolerance and thereby impair exercise performance
§ Types of CHOs – Exogenous: CHO intake from the diet – Endogenous: CHO stored in the body (ie, glycogen) that can be used for
energy needs § Glycogen is stored glucose in the body
– It is a network of glucose molecules connected together, similar to starch
United States An7-‐doping Agency. Op7mal dietary intake guide. Available at: hTp://www.usada.org/diet/?gclid=COOM-‐Ky95aYCFQTNKgodzVQL2w. Accessed January 31, 2011.
Carbohydrates in Diet Carbohydrates are found in the diet as 1. Free monosaccharides (1 sugar unit)
• Glucose (aka dextrose, from corn and other plants)
• Fructose (from fruit)
• Galactose (from milk) 2. Di-‐, tri-‐, oligo-‐ (4 to 10 units), or polysaccharides (chain of 11+ monosaccharides)
• Sucrose (disaccharide of glucose + fructose)
• Lactose (disaccharide of glucose + galactose)
• Maltose (disaccharide of 2 glucose molecules)
• Trehalose (disaccharide of 2 glucose molecules, with a different linkage between the two)
• Starch (polysaccharide of glucose)
Berg JM, et al. Biochemistry. 5th ed. New York, NY: WH Freeman and Co; 2002.
Carbohydrate Diges=on § Carbohydrates are absorbed as monosaccharides § Enzymes must digest di-‐, tri-‐, oligo-‐, and polysaccharides into individual monosaccharides – Enzymes exist in the saliva, stomach, and small intes7ne to break the
different linkages between the various sugars § There are special transporters in the cell membranes of intes7nal cells that selec7vely absorb monosaccharides – Monosaccharides are then transported into the blood stream, where they
are distributed throughout the body § Carbohydrates that escape diges7on and absorp7on make their way to the colon (with variable degrees of bacterial fermenta7on)
Holmes R. J Clin Pathol. 1971;5(suppl):10-‐13.
Why Is Carbohydrate Absorp=on Important in Sports Nutri=on?
§ The ability of the intes7ne to absorb a carbohydrate can be the rate-‐limi7ng step for its delivery to muscle cells for fuel use
§ Enzyme systems in the intes7ne may be insufficient to digest some carbohydrates (eg, lactose intolerance)
§ Intes7nal sugar transporters can become saturated, resul7ng in malabsorp7on of a carbohydrate
§ There are mul7ple transporters for carbohydrates – Ingest a blend of sugars that require different intes7nal transporter systems
(ie, glucose and fructose) • Avoids satura7on of any one transporter
– May increase carbohydrate absorp7on rela7ve to using just a single sugar
Progress Check—Defini=ons, Diges=on, Absorp=on, and Storage 1. Carbohydrates are absorbed in the intes7ne as which of the following?
A. Monosaccharides B. Disaccharides C. Polysaccharides D. All of the above
2. Carbohydrates can influence fluid absorp7on from the intes7ne (hydra7on). A. True B. False
3. Which carbohydrate statement is NOT true? A. Carbohydrate absorp7on can be a rate-‐limi7ng step in delivering fuel to muscles B. Carbohydrates can be digested by enzymes in the saliva, stomach, and small
intes7nes C. All sugars are all absorbed from the intes7nes by a single type of transporter D. Carbohydrates can be a cause of gastrointes7nal intolerance that can nega7vely
affect exercise performance
8
Progress Check—Defini=ons, Diges=on, Absorp=on, and Storage 1. Carbohydrates are absorbed in the intes7ne as which of the
following? A. Monosaccharides
Correct, carbohydrates are absorbed as monosaccharides.
B. Disaccharides Incorrect, please review slide Carbohydrate Diges:on to be;er understand carbohydrate absorp:on.
C. Polysaccharides Incorrect, please review slide Carbohydrate Diges:on to be;er understand carbohydrate absorp:on.
D. All of the above Incorrect, please review slide Carbohydrate Diges:on to be;er understand carbohydrate absorp:on.
9
û
û
û
Progress Check—Defini=ons, Diges=on, Absorp=on, and Storage 2. Carbohydrates can influence fluid absorp7on from the
intes7ne (hydra7on). A. True
Correct, carbohydrates can influence hydra:on.
B. False Incorrect, please review slide Carbohydrates in Sports Nutri:on to be;er understand the effects of carbohydrates on the intes:nes.
10
û
Progress Check—Defini=ons, Diges=on, Absorp=on, and Storage 3. Which carbohydrate statement is NOT true?
A. Carbohydrate absorp7on can be a rate-‐limi7ng step in delivering fuel to muscles Incorrect, please review slide Why Is Carbohydrate Absorp:on Important in Sports Nutri:on? to be;er understand the roles that carbohydrates have in the body.
B. Carbohydrates can be digested by enzymes in the saliva, stomach, and small intes7nes Incorrect, please review slide Carbohydrate Diges:on to be;er understand carbohydrate diges:on.
C. All sugars are all absorbed from the intes7nes by a single type of transporter Correct, only a single type of transporter can absorb carbohydrates in the intes:ne.
D. Carbohydrates can be a cause of gastrointes7nal intolerance that can nega7vely affect exercise performance Incorrect, please review slide Why Is Carbohydrate Absorp:on Important in Sports Nutri:on? to be;er understand the roles that carbohydrates have in the body.
11
û
û
û
Carbohydrate Metabolism
Electron transport
chain
Glucose
CO2 Pyruvate oxidation
Krebs cycle (aka tricarboxylic acid or TCA cycle)
ATP energy
Galactose
Fructose
Glycolysis
Glycogen Glucose intermediate
Berg JM, et al. Biochemistry .5th ed. New York, NY: WH Freeman and Co.; 2002.
Storage of Carbohydrate in the Body § If glucose is absorbed, but not needed right away, the body stores a small amount as glycogen – Glycogen is a fluctua7ng storage pool for glucose – The structure of glycogen is similar to starch – Found in the liver and skeletal muscles
• Glycogen in liver is a reserve glucose supply to the brain • Glycogen in muscles is an energy source for exercise
– Glucose from glycogen breakdown does not leave the muscles
Berg JM, et al. Biochemistry .5th ed. New York, NY: WH Freeman and Co.; 2002.
Glycogen During Exercise § During exercise, glycogen is broken down and glucose molecules enter glycolysis (ie, energy metabolism)
§ Vitamin B6 is a structural part of the enzyme that breaks down glycogen – Shows one of the many roles of B-‐vitamins in energy metabolism
§ Glycogen can supply the body with only a limited amount of energy – Exogenous carbohydrates are important for high-‐intensity and long-‐
dura7on exercise § Eat carbohydrates immediately aper exercise for most rapid glycogen replenishment (recovery) – Inges7on of 50 grams of carbohydrate every 2 hours can result in up to 5%
glycogen replacement per hour • Therefore, total replacement would take 20 hours
Hui YH. Handbook of Food Science, Technology, and Engineering. Volume 1. Boca Raton, FL: CRC Press; 2006:10-‐12. United States An7-‐doping Agency. Op7mal dietary intake guide. Available at: hTp://www.usada.org/diet/?gclid=COOM-‐Ky95aYCFQTNKgodzVQL2w. Accessed January 31, 2011. Tardie G. The Sports Journal. Available at: hTp://www.thesportjournal.org/ar7cle/glycogen-‐replenishment-‐aper-‐exhaus7ve-‐exercise. Accessed February 17, 2011.
Progress Check—Defini=ons, Diges=on, Absorp=on, and Storage 1. Which of the following is referred to as “animal starch”?
A. Glycose B. Glycogen C. Trehalose D. Galactose
2. Muscle glycogen levels can be broken down to supply glucose for the bloodstream when blood glucose is low. A. True B. False
15
Progress Check—Defini=ons, Diges=on, Absorp=on, and Storage 1. Which of the following is referred to as “animal starch”?
A. Glycose Incorrect, please review slide Storage of Carbohydrate in the Body to be;er understand carbohydrate storage.
B. Glycogen Correct, the structure of glycogen is similar to starch in plants.
C. Trehalose Incorrect, please review slide Storage of Carbohydrate in the Body to be;er understand carbohydrate storage.
D. Galactose Incorrect, please review slide Storage of Carbohydrate in the Body to be;er understand carbohydrate storage.
16
û
û
û
Progress Check—Defini=ons, Diges=on, Absorp=on, and Storage 2. Muscle glycogen levels can be broken down to supply
glucose for the bloodstream when blood glucose is low. A. True
Incorrect, please review slide Glycogen During Exercise to be;er understand the use of glycogen in the body.
B. False Correct, glucose from muscle glycogen breakdown does not leave the muscles.
17
û
II. Proper=es of Carbohydrates:
Considera7ons for Sports Performance
Glycemic Response to Carbohydrates in Sports Nutri=on
§ Inges7on of carbohydrates affects both blood glucose levels and insulin response (glycemic response)1 – Can influence energy sources during exercise
§ One measure of glycemic response is the glycemic index (GI)2,3 § Glycemic load is a rela7vely new measure for glycemic response4 – Based on the concept that exercise performance may be determined by
both carbohydrate inges7on and the glycemic response of the overall diet
19
1. Mondazzi L and Arcelli E. J Am Coll Nutr. 2009;28:455S-‐463S. 2. Burke LM, et al. Int J Sport Nutr. 1998;8:401-‐415. 3. Donaldson CM, et al. Int J Sport Nutr Exerc Metab. 2010;20:154-‐165. 4. O’Reilly J, et al. Sports Med. 2010;40:27-‐39.
What Is the Glycemic Index? § System of ranking foods according to how much they raise blood glucose rela7ve to a reference food – Developed by Jenkins DJ, et al. Am J Clin Nutr. 1981;34(3):362-‐366.
§ Rapidly digested or absorbed carbohydrates = high GI § Slowly digested or absorbed carbohydrates = low GI § References on GI
– Brand-‐Miller J, et al. The New Glucose RevoluJon. 3rd ed. New York, NY: Marlowe & Co.; 2006 • WriTen by experts on GI
– Atkinson, et al. Diabetes Care. 2008;31(12):2281-‐2283 • Most comprehensive table of the
glycemic index of foods that has been assembled to date
Abbrevia7ons: GI, glycemic index. Figure from hTp://www.glycemicindex.com/aboutGI.htm.
What Does the Glycemic Index Value Mean?
§ The glycemic index (GI) is expressed as a ra7o comparing the blood glucose increase caused by a test food to that of a reference food (usually glucose, historically white bread) for 2 hours following inges7on:
§ GI values: Split peas = 25 ± 6 Golden delicious apples = 39 ± 3 Oatmeal = 51 ± 8 Raisin bran flake type of cereal = 61 ± 5 White bread = 75 ± 2 Long-‐grain white rice = 76 ± 7 Corn flake type of cereal = 81 ± 3
Atkinson FS, et al. Diabetes Care. 2008;31(12):2281-‐2283.
Area Under the Curve for Test Food
Area Under the Curve for Reference Food × 100 = GI
Slow and Fully Digested CHOs (Low GI) § Isomaltulose1
– Glucose and fructose – More steady and sustained release of glucose into the blood compared with
sucrose – Occurs naturally in honey, but can be synthesized from sucrose
§ Sucromalt2 – Produced by enzyma7c conversion of sucrose and maltose into a fructose
and oligosaccharide syrup • ~40% fructose, ~50% oligosaccharides, and ~10% other mono-‐ and disaccharides
– Diges7on profile similar to isomaltulose § Gamma-‐cyclodextrin (γ-‐CD)3
– Ring of 8 glucose molecules
+
Abbrevia7ons: CHO, carbohydrate; GI, glycemic index. 1. Lina BA, et al. Food Chem Toxicol. 2002;40(10):1375-‐1381. 2. Xtend™ Sucromalt. Cargill, Inc. Available at: hTp://www.cargill.com/food/na/en/products/sweeteners/specialty-‐sweeteners/xtend-‐sucromalt/index.jsp. Accessed February 24, 2011. 3. Munro IC, et al. Regul Toxicol Pharmacol. 2004;39:S3-‐13.
What Is the Glycemic Load? § Takes into account the amount of carbohydrate in a common serving in addi7on to its glycemic index
§ Example – Carrots (peeled, boiled) have a GI of 47 and 5 g CHO per serving
The GL of carrots is: (47 × 5) ÷ 100 = 2.4
GL = (GI of CHO × gram CHO per serving) ÷ 100
Abbrevia7ons: CHO, carbohydrate; GL, glycemic load; GI, glycemic index. Atkinson FS, et al. Diabetes Care. 2008;31(12):2281-‐2283.
Glycemic Index and Load Standards for Foods
§ GI (based on glucose reference) – Low GI 0-‐55 – Intermediate GI 56-‐69 – High GI ≥ 70
§ GL – Low GL 0-‐10 – Intermediate GL 11-‐19 – High GL ≥ 20
Abbrevia7ons: GI, glycemic index; GL, glycemic load. Brand-‐Miller J, et al. The New Glucose RevoluJon: The AuthoritaJve Guide to the Glycemic Index-‐The Dietary SoluJon for Lifelong Health. 3rd ed. New York, NY: Marlowe and Co.; 2006. Brand-‐Miller JC, et al. Am J Clin Nutr. 2003;77(4):993-‐995.
Limita=ons of Glycemic Index During Exercise
§ Clinical data have been mixed regarding the role of the glycemic index (GI) in food choice before exercise – Results suggest that inges7on of foods with a low GI before exercise may
• ATenuate the glycemic response • Maintain carbohydrate availability during exercise
§ Clinical results also suggest that moderate to high GI foods may aid in carbohydrate availability when ingested during exercise
§ Differen7al inges7on of low vs high GI foods before or during exercise has not yet translated into clear performance benefits
25
Burke LM, et al. Int J Sport Nutr. 1998;8:401-‐415. Donaldson CM, et al. Int J Sport Nutr Exerc Metab. 2010;20:154-‐165.
What Is High-‐Fructose Corn Syrup? § Cornstarch is converted to corn syrup that is essen7ally 100% glucose
§ Enzymes and processing techniques convert some of the glucose to fructose to achieve corn syrup that is 55% fructose (HFCS-‐55)
§ HFCS-‐55 is the type of corn syrup used mainly in the beverage industry – Syrup is 55% fructose, 45% glucose – Similar to sucrose (table sugar; 50% fructose, 50% glucose)
§ The term “high-‐fructose corn syrup” is a liTle misleading – Because corn syrup is 100% glucose, any presence of fructose typically
results in it being labeled “high-‐fructose corn syrup”
Soenen S, et al. Am J Clin Nutr. 2007;86(6):1586-‐1594. Smith JS, et al. Food Processing: Principles and ApplicaJons. Ames, IA: Blackwell Publishing; 2004:212-‐214.
The Truth About High-‐Fructose Corn Syrup § Too much sugar, of any kind, in beverages is not recommended
– It is easy to consume too much energy, leading to weight gain – Most sugar-‐sweetened beverages provide liTle to no vitamins, minerals, or
other essen7al nutrients § However, there are no differences in metabolic responses to high-‐fructose corn syrup vs sucrose in humans – No differences in circula7ng hormones – No differences in appe7te or sa7ety-‐related variables (fullness)
DiMeglio DP, et al. Int J Obesity. 2000;24:794-‐800. Melanson KJ, et al. NutriJon. 2007;23(2):103-‐112. Stanhope KL, et al. Am J Clin Nutr. 2008;87(5):1194-‐1203. Soenen S, et al. Am J Clin Nutr. 2007;86(6):1586-‐1594.
Progress Check—Considera=ons for Sports Performance 1. Inges7on of low versus high glycemic index foods before or during exercise
has clear performance benefits. A. True B. False
2. Glycemic load is based on which of the following concepts? A. Only carbohydrate inges7on determines exercise performance B. Only the glycemic response of the overall diet determines exercise
performance C. Both the amount of carbohydrate per serving and the glycemic index of that
carbohydrate influence the blood glucose response D. Stored glycogen in muscles determines exercise performance
3. In humans, metabolic responses to high-‐fructose corn syrup are similar to which of the following? A. Glucose B. Glycogen C. Fructose D. Sucrose
28
Progress Check—Considera=ons for Sports Performance 1. Inges7on of low versus high glycemic index foods before or
during exercise has clear performance benefits. A. True
Incorrect, please review slide Limita:ons of Glycemic Index During Exercise to be;er understand the effects of glycemic index foods on performance during exercise.
B. False Correct, intake of low versus high glycemic index foods before or during exercise has not shown clear performance benefits.
29
û
Progress Check—Considera=ons for Sports Performance 2. Glycemic load is based on which of the following concepts?
A. Only carbohydrate inges7on determines exercise performance Incorrect, please review slide What Is the Glycemic Load? to be;er understand the calcula:on and defini:on of glycemic load.
B. Only the glycemic response of the overall diet determines exercise performance Incorrect, please review slide What Is the Glycemic Load? to be;er understand the calcula:on and defini:on of glycemic load.
C. Both the amount of carbohydrate per serving and the glycemic index of that carbohydrate influence the blood glucose response Correct, both amount and glycemic index of carbohydrates influence glucose response.
D. Stored glycogen in muscles determines exercise performance Incorrect, please review slide What Is the Glycemic Load? to be;er understand the calcula:on and defini:on of glycemic load.
30
û
û
û
Progress Check—Considera=ons for Sports Performance 3. In humans, metabolic responses to high-‐fructose corn syrup
are similar to which of the following? A. Glucose
Incorrect, please review slide The Truth About High-‐Fructose Corn Syrup to be;er understand the body’s response to high-‐fructose corn syrup.
B. Glycogen Incorrect, please review slide The Truth About High-‐Fructose Corn Syrup to be;er understand the body’s response to high-‐fructose corn syrup.
C. Fructose Incorrect, please review slide The Truth About High-‐Fructose Corn Syrup to be;er understand the body’s response to high-‐fructose corn syrup.
D. Sucrose Correct, the body metabolizes high-‐fructose corn syrup similarly to sucrose.
31
û
û
û
III. Training
Carbohydrates and Sports Nutri=on § Important for maximizing muscle glycogen stores
– Depleted muscle glycogen—“Hi}ng the wall” – Depleted liver glycogen—“Bonking” – Both phenomena are experienced as a precipitous loss of energy as a result
of low blood sugar § Training and high carbohydrate diets maximize glycogen stores
United States An7-‐doping Agency. Op7mal dietary intake guide. Available at: hTp://www.usada.org/diet/?gclid=COOM-‐Ky95aYCFQTNKgodzVQL2w. Accessed January 31, 2011. Ensminger A. Foods and NutriJon Encyclopedia 2nd EdiJon Volume 1. Boca Raton, FL: CRC Press LLC; 1994. Pages 1202-‐1203. Burke L. PracJcal Sports NutriJon. Champaign, IL: Human Kine7cs; 2007. Page 124. Clark N. Sports NutriJon Guidebook 4th EdiJon. Champaign, IL: Human Kine7cs; 2008. Page 119.
Carbohydrate and Fat Use at Different Exercise Intensi=es
§ As the intensity of exercise increases, muscle glycogen cons7tutes a greater por7on of the energy source
Abbrevia7ons FFA, free faTy acid. Romijn JA, et al. Am J Physiol. 1993;265(Part 1):E380-‐E391.
(Weightlifting, sprinting, etc)
(Leisurely walking, slow cycling)
(Soccer, dancing, etc) Muscle glycogen
Muscle triglyceride
Plasma FFA
Plasma glucose
300
200
100
0
Energy Expen
ded, cal/kg/min
25 65 85 Maximal Oxygen Consump=on, %
Carbohydrates in the Days Before Exercise § High glycogen stores are very important to prolong endurance – Related to diet and exercise in the days and hours before exercising/
compe7ng – Endogenous carbohydrate oxida7on occurs at high intensity – Especially important for events longer than 90-‐120 minutes
(eg, marathons and cycling events)
United States An7-‐doping Agency. Op7mal dietary intake guide. Available at: hTp://www.usada.org/diet/?gclid=COOM-‐Ky95aYCFQTNKgodzVQL2w. Accessed January 31, 2011. LaTa S. Marathon & Beyond. 2003;7(5).
Carbohydrates 1 to 2 Hours Before Exercise
§ Low glycemic index foods and beverages – Especially important for endurance exercise
§ Carbohydrates that are also low in fiber may be beneficial due to varied gastrointes7nal sensi7vity among individuals – Examples
• Fruit juices • Bagels • Breakfast cereals with < 3 g fiber/serving • Potatoes
§ Carbohydrate amounts vary among individuals, sport type, and sport intensity
United States An7-‐doping Agency. Op7mal dietary intake guide. Available at: hTp://www.usada.org/diet/?gclid=COOM-‐Ky95aYCFQTNKgodzVQL2w. Accessed January 31, 2011. Wu CL and Williams C. Int J Sport Nutr Exerc Metab. 2006;16(5):510-‐527.
Carbohydrates During Exercise Are Also Important
§ Jeukendrup (2004) reviewed mul7ple studies (n = 22) of walking, running, and cycling in which carbohydrates were given during exercise – 23 of 36 observa7ons within these studies showed a posi7ve effect of
carbohydrate on endurance – Effec7ve dose
• Minimum, 16 to 22 g carbohydrate/hour • Maximum, 75 g carbohydrate/hour
– No studies showed an adverse, or ergoly7c, effect of carbohydrate on performance
– Form of carbohydrate (solid or liquid) was of liTle significance, although the vast majority of the studies used a beverage
§ Sports beverages that include different types of sugars will be absorbed via different sugar transporters in the gut – Increase exogenous carbohydrate oxida7on during exercise from 1.0 g/min
to 1.2 to 1.5 g/min
Jeukendrup AE. NutriJon. 2004;20(7-‐8):669-‐677.
Carbohydrates Afer Exercise § Carbohydrates that are quickly digested and absorbed are recommended postexercise to restore muscle glycogen levels as fast as possible – Glucose – Maltose – Maltodextrin
§ Protein + carbohydrates postexercise maximizes the rate of glycogen synthesis
§ When intervals between exercise sessions are < 8 hours, consume carbohydrates as soon as prac7cal postexercise for fastest recovery
Ivy JL, et al. J Appl Physiol. 2002;93:1337-‐1344.
Recommenda=ons for Carbohydrate Intake During Recovery
§ Carbohydrate intakes are expressed per kga not % of energy – For immediate recovery aper exercise (0 to 4 hours)
• 1.2 g/kg/hr consumed at frequent intervals – For daily recovery
• Moderate dura7on/low intensity exercise – 5 to 7 g/kg/day
• Moderate to heavy endurance training – 7 to 12 g/kg/day
• Extreme exercise program (≥ 4 to 6 hours/day) – 10 to 12+ g/kg/day
aMul7ply the numbers by 0.45 to get carbohydrate intake in grams per pound of body weight. Burke LM, et al. J Sport Sci. 2004;22(1):15-‐30.
Pugng Together a Meal Plan § Example:
– 70-‐kg athlete requiring 4000 kcal/day and exercising 120 min/day 4 to 6 7mes/week
§ Macronutrient Target Recommenda7ons – Grams/kg (body weight)/day
• Carbohydrate 7 to 10 g/kg/day (490 to 700 g/day) • Protein 1.5 to 2.0 g/kg/day (105 to 140 g/day) • Fat Typically use percentage of energy as method
– Percentage of energy • Carbohydrate 55% to 65% of energy (550 to 650 g/day) • Protein 10% to 15% of energy (100 to 150 g/day) • Fat 20% to 30% of energy (88 to 133 g/day)
– Target recommenda7ons for this athlete • Carbohydrate 600 g (60% of energy) • Protein 130 g (13% of energy) • Fat 120 g (27% of energy)
A Poten=al Distribu=on of Macronutrients Over the Course of 6 Meals/Day
Meal Time Carbohydrate, g Protein, g Fat, g
Breakfast 7:00 AM 90 15 15
Mid-‐AM snack 10:00 AM 25 10 5
Lunch Noon 75 20 20
Pre-‐Ex meal 1:30 -‐ 2:00 PM 90 10 5
During Ex 3:00 -‐ 5:00 PM 100 0 0
Post-‐Ex meal 5:00 PM 75 30 25
Dinner 6:30 PM 120 30 35
PM snack 9:00 PM 25 15 15
TOTALS 600 130 120
Foods Containing Approximately 25 to 30 g Carbohydrate
§ 1 cup of juice or 1 large piece of fruit § 1 bagel or 2 slices of bread § 1 cup of most cereals § 1 large baked potato § 2 cups of milk § ⅔ cup of dried beans § 1 cup of rice or corn § 1 cup of squash (other non-‐starchy vegetables have less carbohydrate)
§ 2 cups of commercial sports/electrolyte replacement drink § ½ to 1 energy bar (1 bar ≅ 25 to 45 g carbohydrate) § 1 pack of energy gel (≅ 25 g carbohydrate)
Atkinson FS, et al. Diabetes Care. 2009;31(12):2281-‐2283.
Examples of Postexercise Meals § Op7on 1
– 1 regular bagel – 2 Tablespoons peanut buTer – 8 fl oz skim milk – 1 medium banana § Meal provides 562 kcal, 77 g carbohydrate, 23 g protein, and 18 g fat
§ Op7on 2 – 17-‐oz commercial nutri7on shake § Provides 300 to 420 kcal, 17 to 70 g carbohydrate, 32 to 42 g protein,
and 2 to 16 g fat
Progress Check—Training 1. Carbohydrate consump7on during extended (greater than 45 minutes)
exercise usually improves performance. A. True B. False
2. Which of the following carbohydrate intakes would be most appropriate for a training endurance athlete (exercising 4-‐5 hours/day) who requires daily recovery? A. 1 g per pound body weight per day B. 10-‐12+ g/kg body weight per day C. 1500 g/day D. All of the above intakes are too low
3. Maximal glycogen stores are important for endurance. A. True B. False
44
Progress Check—Training 1. Carbohydrate consump7on during extended (greater than
45 minutes) exercise usually improves performance. A. True
Correct, carbohydrate consump:on during long exercise periods can improve performance.
B. False Incorrect, please review slide Carbohydrates During Exercise Are Also Important to be;er understand the effects of carbohydrate consump:on on performance during exercise.
45
û
Progress Check—Training 2. Which of the following carbohydrate intakes would be most
appropriate for a training endurance athlete (exercising 4-‐5 hours/day) who requires daily recovery? A. 1 g per pound body weight per day
Incorrect, please review slide Recommenda:ons for Carbohydrate Intake During Recovery to be;er understand the various carbohydrate intake recommenda:ons for recovery.
B. 10-‐12+ g/kg body weight per day Correct, an extreme exercise regimen needs this amount of carbohydrate intake for daily recovery.
C. 1500 g/day Incorrect, please review slide Recommenda:ons for Carbohydrate Intake During Recovery to be;er understand the various carbohydrate intake recommenda:ons for recovery.
D. All of the above intakes are too low Incorrect, please review slide Recommenda:ons for Carbohydrate Intake During Recovery to be;er understand the various carbohydrate intake recommenda:ons for recovery.
46
û
û
û
Progress Check—Training 3. Maximal glycogen stores are important for endurance.
A. True Correct, glycogen becomes important during high intensity and long exercise periods.
B. False Incorrect, please review slide Carbohydrates in the Days Before Exercise to be;er understand the role of glycogen in exercise.
47
û
IV. Compe==ons
Compe==on § Compe77ons some7me require different carbohydrate intakes than prac7ce – Endurance may be required for a longer amount of 7me – Maximum glycogen levels are op7mal for best performance and require
7me to build (on the order of days; not possible for prac7ces) § Do not try any new foods in compe77on before you try it at least once at prac7ce
Carbohydrates as Energy at Different Times
§ Carbohydrate consumed in the days before event – Used to provide adequate glycogen stores in muscle
• Prevent “hi}ng the wall” § Carbohydrate consumed in the hours before the event
– Used to preserve liver glycogen stores, which can deplete aper approximately 8 to 12 hours of fas7ng
§ Carbohydrate consumed during event – Used to maintain blood glucose, especially when liver glycogen is depleted
• Carbohydrate in the hours before and during exercise helps to prevent “bonking”
United States An7-‐doping Agency. Op7mal dietary intake guide. Available at: hTp://www.usada.org/diet/?gclid=COOM-‐Ky95aYCFQTNKgodzVQL2w. Accessed January 31, 2011. Ensminger A. Foods and NutriJon Encyclopedia 2nd EdiJon Volume 1. Boca Raton, FL: CRC Press LLC; 1994. Pages 1202-‐1203. Burke L. PracJcal Sports NutriJon. Champaign, IL: Human Kine7cs; 2007. Page 124. Clark N. Sports NutriJon Guidebook 4th EdiJon. Champaign, IL: Human Kine7cs; 2008. Page 119.
Carbohydrate Loading § Tradi7onal protocol
– Deple7on of glycogen stores (~ days 6 to 3 before event) • Low-‐carbohydrate diet and hard exercise
– Supercompensa7on of muscle glycogen (~ day 3 before event to day of event) • Very high-‐carbohydrate diet (8 to 12 g/kg body weight/day) and tapering of exercise
§ Cons – Deple7on phase is hard on the body and difficult to tolerate
in training • May lead to headaches, irritability, and increased risk of injury
Pre-‐Compe==on Meal § One of the most variable aspects of the athlete’s diet
– Depends on individual tolerance – Athletes open have certain beliefs about food’s effect
on performance – Ranges from no food to the old “steak and eggs” breakfast – Depends on the sport to some degree
§ Func7ons of the pre-‐event meal – Prevent dehydra7on – Maintain adequate muscle and liver glycogen levels – Avoid excess hunger feelings – Confidence in prepara7on for the event
Pre-‐Compe==on Meal (con=nued) § Medium amount of energy
– 300 to 500 kilocalories, more if there is 7me to digest before the event § 2 to 3 hours before event (perhaps 1 hour with liquid meal)
– Inges7on of carbohydrate 1 hour before exercise does not usually impair performance
– Depends on individual tolerance § Liquid meals are popular for gastrointes7nal comfort during the event
§ GI of pre-‐event carbohydrates – Low GI is recommended for endurance or high-‐intensity events
§ Include 1 to 2 cups of fluid § Avoid foods with a high fat content and/or excess fiber
Abbrevia7ons: GI, glycemic index.
1. Clark N. Sports NutriJon Guidebook. Champaign, IL: Human Kine7cs; 1989.
Food Kcal Carbohydrate, g Protein, g Fat, g Oatmeal, instant 1 pkt 104 18 4 2
Skim milk, ½ cup 43 6 4 0
Toast, 2 slices 146 24 4 2
Banana, 1 medium 105 27 0 1
Orange juice, 6 oz 84 20 1 0
TOTAL 482 95 (80%) 13 (11%) 5 (9%) Abbrevia=ons: CHO, carbohydrate; pkt, packet.
Examples of Pre-‐Compe==on Meals § Op7on 1, liquid meal (blend all ingredients)1
– 1 cup of vanilla yogurt – 4 to 6 peach halves, canned or fresh – 4 graham cracker squares – Dash nutmeg, op7onal § Meal provides 450 kcal, 75% CHO, 15% protein, and 10% fat
§ Op7on 2
Carbohydrates During Compe==on § Carbohydrate intake of 30 to 60 g/hour during endurance exercise
– Consumed at 10-‐ to 30-‐minute intervals – 1 cup of commercial sports drink has ~14 g (6%) – Liquid form of carbohydrate (ie, sports drink) also helps with hydra7on
§ In general, do not exceed – 60 to 90 g/hour carbohydrate intake
• 90 g/hour should consist of carbohydrates that use mul7ple transporters – More than 7% to 8% carbohydrates in beverages
• Due to poten7al for gastrointes7nal distress – Be aware of sugar alcohols and large amounts of fructose
• A maTer of individual tolerance – Find your op7mal range – Try first in prac7ce, not compe77on
Jeukendrup AE. NutriJon. 2004;20(7-‐8):669-‐677. Burke LM, et al. J Sport Sci. 2004;22(1):15-‐30.
Progress Check—Compe==ons 1. Which of the following nega7ve effects is associated with the deple7on
phase of the carbohydrate loading protocol? A. Kidney stones B. Headaches C. Dehydra7on D. Hyperglycemia
2. Which of the following is a benefit of a pre-‐compe77on meal? A. Improved flexibility B. Reduced stress C. Improved immune system D. Improved hydra7on E. All of the above
3. When consuming carbohydrates during endurance exercise, it is best not to exceed what intake level? A. 10 to 19 g/hr B. 20 to 39 g/hr C. 40 to 59 g/hr D. 60 to 90 g/hr 56
Progress Check—Compe==ons 1. Which of the following nega7ve effects is associated with
the deple7on phase of the carbohydrate loading protocol? A. Kidney stones
Incorrect, please review slide Carbohydrate Loading to be;er understand the pros and cons of carbohydrate loading.
B. Headaches Correct, headaches, irritability, and increased risk of injury may occur during the deple:on phase of the carbohydrate loading protocol.
C. Dehydra7on Incorrect, please review slide Carbohydrate Loading to be;er understand the pros and cons of carbohydrate loading.
D. Hyperglycemia Incorrect, please review slide Carbohydrate Loading to be;er understand the pros and cons of carbohydrate loading.
57
û
û
û
Progress Check—Compe==ons 2. Which of the following is a benefit of a pre-‐compe77on meal?
A. Improved flexibility Incorrect, please review slide Pre-‐Compe::on Meal to be;er understand the benefits of a pre-‐compe::on meal.
B. Reduced stress Incorrect, please review slide Pre-‐Compe::on Meal to be;er understand the benefits of a pre-‐compe::on meal.
C. Improved immune system Incorrect, please review slide Pre-‐Compe::on Meal to be;er understand the benefits of a pre-‐compe::on meal.
D. Improved hydra7on Correct, preven:ng dehydra:on, maintaining adequate muscle and liver glycogen levels, and avoiding excess hunger feelings are all benefits of a pre-‐compe::on meal.
E. All of the above Incorrect, please review slide Pre-‐Compe::on Meal to be;er understand the benefits of a pre-‐compe::on meal.
58
û
û
û
û
Progress Check—Compe==ons 3. When consuming carbohydrates during endurance exercise, it
is best not to exceed what intake level? A. 10 to 19 g/hr
Incorrect, please review slide Carbohydrates During Compe::on to be;er understand the recommended carbohydrate intakes during exercise.
B. 20 to 39 g/hr Incorrect, please review slide Carbohydrates During Compe::on to be;er understand the recommended carbohydrate intakes during exercise.
C. 40 to 59 g/hr Incorrect, please review slide Carbohydrates During Compe::on to be;er understand the recommended carbohydrate intakes during exercise.
D. 60 to 90 g/hr Correct, it is recommended to not exceed a carbohydrate intake of 90 g/hr.
59
û
û
û
Summary of Key Messages § A high-‐carbohydrate diet helps to maximize glycogen stores and generally increases exercise performance
§ Knowledge of the glycemic index of carbohydrates can be helpful in choosing the right carbohydrate at the right =me
§ Consuming carbohydrate during exercise also generally helps performance – Experiment in prac7ce regarding tolerated levels – Liquid carbohydrates also help with hydra7on
§ Ea=ng as soon as possible afer exercise promotes the most rapid recovery of muscle glycogen – Combina7on of carbohydrate and protein may facilitate this process
§ Frequent, smaller meals can help athletes with high energy and carbohydrate requirements get in the required amounts of nutrients
© 2013 AbboT Laboratories The EAS ACADEMY™ website and its content is owned by AbboT Nutri7on, a division of AbboT Laboratories. All rights reserved. Any redistribu7on or reproduc7on of any part or all of the contents in any form is prohibited other than the following: 1. you may print or download to a local hard disk extracts for your personal and non-‐commercial use only; 2. you may copy the content to individual third par7es for their personal use, but only if you acknowledge the website as the source of the material. You may not, except with our express wriTen permission, distribute or commercially exploit the content.
61
