Nutrition in Sports

1. Nutrition in Sports MAJ Michael R. Simpson, DO Sports Medicine Fellow VCU- Fairfax Family Practice February 2008

2. Objectives • Understand basic concepts of pre-race, race, and post-race nutrition • Discuss basic hydration and prevention of exertional hyponatremia strategies • Be able to educate athletes about the facts and fallacies of endurance sports nutrition

3. Endurance Athlete Questions • Training and game day….should I and how do I carbo load? • What combo of carbs, fat, and protein is best prior to the race and long distance training? • During training and game day • Water or sports drink? How much do I need to drink? • Gels, carbs, or protein? • How many calories and how often? • Will caffeine help me perform better?

4. Endurance Athlete Questions • After the race or game: • What and how much should I drink? • What should I eat? • When should I eat? • Are there any proven legal sports supplements that I can use to improve my performance?

5. Keys to Endurance Performance • Maximize and maintain fuel (glycogen) supplies • Maintain and optimize hydration and electrolyte balance • Prevent protein breakdown and maximize synthesis • Efficient and timely recovery from prior bout of exercise

6. Let’s Talk Carbohydrates • Carbos (CHO) converted to glycogen and stored in muscles and liver. • Glycogen is #1 fuel source for endurance events of moderate to high intensity • Glycogen repletion is slow and recovery time is directly related to ability to replenish • Maintaining and restoring glycogen is key to performance

7. Let’s Talk Carbohydrates • Carbo loading • Old school: One week low carbs (deplete) with 1-3 day high carbs prior • New school: 3 days of high carbo diet before race or long distance training session • Events longer than 60-90 minutes • Goal: Pre-training/race build up glycogen stores to prevent “bonking” or “hitting the wall”

8. Low CHO diet (40% kcal from CHO) Double cheeseburger Medium fries Chocolate milkshake High CHO diet (70% kcal from CHO) 12 inch sub sandwich (lots of vegetables & no mayo) 500 ml apple juice 250 ml chocolate milk banana Comparison of Diets

9. Effects of Diet on Muscle Glycogen Content 140 120 100 High CHO 80 Low CHO 60 Muscle Glycogen (mM/kg wet wt) 40 20 0 Day 1 Day 2 Day 3 Time

10. Let’s Talk Carbohydrates(Training and Game/Race Day) • Training and race day diet should consist of: • CHO: 55-70 % (6-10 grams per kilogram of body weight or 8-10 kcals per kilogram) • Fats: 25-30% (no benefit to extra) • Protein: 12-15% (1.0-1.5 grams per kilogram) of high quality protein

11. Carbohydrate Snacks • Foods supplying 50 grams CHO • 500 ml juice • 3 medium pieces of fruit • 1 honey sandwich • 2 breakfast bars • 1 sports bar (check label) • 1.3 bagels • 1/2 cup dried fruit • 1 cup white rice • 1 baked potato *average 70 kg endurance athlete should consume 560 grams CHO per day

12. Sport Bars • Developed to provide an easily accessible source of CHO • Many bars provide complex proteins and may be high in fat. • Vary in type and amount of energy, CHO, protein and fat. • Some provide only 150 kcal andothers up to 340 kcal • Many contain other agents, herbs, etc • READ LABELS CLOSELY! *average sports bar provides about 40-60 grams of CHO

13. Atkins Advantage Bar Balance Bar Bioprotein Bar Clif Bar Detour Bar Gatorade Energy Bar GeniSoy Ironman Triathlon Bar Low Carb Keto-Bar Luna Bar Metabolift Bar Met-Rx PowerBar PremierNutrition Bar Protein Revolution Low Carb Bar Think Divine Tiger’s Milk ZonePerfect Sugar-Free ProteinPlus Ultimate Low-Carb Bar Brands of Sports Bars

14. Sport Gels • Designed to deliver large amount of CHO in compact and easily consumed form • Very slowly absorbed by body and must have adequate amounts of water to dilute and lower osmolality   • Gels may be effective source of energy, but challenge is taking in enough fluid. • About 100 calories per package (25 grams CHO)

15. Brands of Sport Gels • e-Gel • GU • Power Gel • Clif Shot • Hammer Gel

16. Composition of Sport Gels

17. Glycemic Index and Insulin Response Index Glycemic Index (GI): • Ranking of food based on blood glucose response to reference food • High GI (dextrose and maltose): Evoke large increases in glucose • Carrots, raisins, corn flakes, breads, rice cakes • Low/Moderate GI (sucrose and lactose): Evoke small/modest increases in glucose. • i.e.. Yogurt, apples, dried fruit, lentils, beans Insulin Response Index (IRI): • Ranking of food based on blood insulin response to same reference food

18. GI > 85 White Bagel English Muffins Doughnut Raisins Corn Chips Ice Cream Sports Drinks GI < 60 Yogurt Grapefruit/Oranges Beans Peanuts Apples/Pears/Plums Milk Brown Rice Glycemic Index of Foods

19. Practical Use of GI and IRI • Pre-race/training • Low to moderate best to build up glycogen stores, avoid glucose-insulin spikes, GI tolerability • During race • Moderate to high is best for sustained energy

20. Honey Fructose Power Gel™ Sucrose Dextrose Maltodextrin Comparison of CHOs in Gel Products IRI CHO GI 5 35 43 71 100 121 41 59 113 147 100 158 Research funded by the National Honey BoardRichard Kreider, PhD

21. Concerns with Sport Gels • High cost alternative • Some brands also contain other compounds • Gastrointestinal intolerance • Should be usedduring training to assess tolerance for use during race • May lead to over consumption/over-reliance on low-nutrient CHO sources

22. Carbos During The Race/Training • Events lasting longer than 60 minutes • Ingest 30-60 grams of CHO per hour (2 gel packs) • GI tolerable • With water • Prevent “bonking”

23. Carbos After The Race/Training • Timing is everything • To replenish glycogen stores after exercise, 1.0 - 1.5 grams of CHO/kg body weight should be ingested within 30 min and repeated every 2 hr for 4 to 6 hr. • Add a little protein Van Hall G et al. J Appl Physiol. 2000;88:1631-6.

24. Muscle Glycogen Resynthesis Rate Muscle Glycogen (nmol/kg) Recovery Time (hr) van Hall G et al. J Appl Physiol. 2000.

25. Carbo Summary For Your Athlete • For long training runs and game day • 60-70% CHO diet for 3 days prior, and decrease the training load • Use low GI foods • Avoid high GI foods 1-3 hours before run/race • During run/race • Moderate to high GI source • 100 calories every 20-30 minutes for sessions longer than 60 minutes • After run/race • Carbs within 30 minutes and continued for the rest of the day; some protein • Practice your nutrition; never try something new on race day!

26. Protein Balance Bottom Line • Positive protein/AA balance is important in muscle recovery • 4:1 carbo to protein replacement after exercise probably helpful • More research needed

27. Hydration and Electrolyte Balance • WATER IS MOST ESSENTIAL NUTRIENT • 60% of body is water • 75% of skeletal muscle is water • Important functions of water • Makes up plasma, which transports and delivers nutrients to tissues • Maintains body temperature and pH • Maintains blood circulation and pressure • Supports energy processes

28. Fluid Balance

29. Dehydration and Performance

30. 12 3 4 5 6 7 8 9 Monitoring HydrationStatus Urine color test for dehydration Lemonade—The good Apple juice—The bad Tea—The ugly

31. Indices of Hydration

32. Establishing Fluid Needs • Estimate sweat rate or amount of fluid lost in a specified period of time during defined exercise workload • A: Body weight: Pre - Post • B: Fluid intake: Total volume • C: Urine volume • Sweat loss = A + B - C • Sweat rate = Sweat loss/time

33. Example of Fluid Needs • Body weight • Before = 70 kg and after = 67 kg • Fluid intake = 1.8 L • Urine volume = 0.7 L • Time = 2 hours or 120 min. • Sweat loss = (3 + 1.8 - 0.7) = 4.1 • Sweat rate = 4.1 L/2 hrs = 2.05 L/hr

34. Pre-Exercise Hydration Guidelines • Obtain body weight. • Check color of morning urine - pale color (1 - 3) indicates a good hydration status • Drink 16 to 20 fl oz of water or sports beverage 2 to 3 hrs before • Drink 8 to 12 fl oz of water 0 to 10 min before exercise

35. During Exercise Hydration Guidelines • Drink 3-8 fl oz of water every 15-20 min when exercising for < 60 min • Drink 3-8 fl oz of a beverage with CHO (5% to 8%) and sodium every 15-20 min when exercising> 60 min • DO NOT DRINK MORE THAN 1 L or 1 Qt/hr during exercise *One size does not fit all!

36. Post-Exercise Hydration Guidelines • Obtain body weight to estimate fluid losses and correct losses within 2 hrs • Consume 1 liter of fluid for every liter lost • When re-hydrating rapidly, ingest 25% more than sweat losses to assure optimal hydration within 4 to 6 hrs after exercise • Beverage should contain water to restore hydration status, CHO to replenish glycogen stores, some protein, and sodium to accelerate re-hydration

37. ACSM Position • Thirst is not the best hydration indicator for active people and those who are exposed to heat • Athletes should replace fluids in amounts that approximate sweat losses.

38. Hydration Guidance For Your Runner • Monitor morning hydration and pre-hydrate • Estimate your sweat rate and replace (600-1000 ml per hour) • Never gain weight! • Salty sweater….salt supplement • Sports drinks for > 60 minute • Resist temptation to drink at every water stop • Thirst is a poor indicator of hydration status

39. Endurance Event Performance Enhancement • EPO = illegal • RBC transfusion = illegal • Caffeine does improve endurance performance within legal limits • USADA: www.usantidoping.org

40. Summary • Nutrition and hydration are key elements to performance • High carb diet with protein and some fat • Timing is important • Sports drink versus water • Never gain weight and consider salt supplement • Practice your nutrition and hydration; never experiment on race day!

41. References • American College of Sports Medicine: American Dietetic Association and Dietitians of Canada: Joint position statement nutrition and athletic performance. Med Sci Sports Exerc 2130-2138, 2000. • DiMarco NM, Samuels M: Nutritional considerations, in O’Connor FG, Wilder RP (eds): Textbook of Running Medicine, New York, NY, McGraw Hill 2001, pp 469-477. • Casa D.J.,  Armstrong L.E.,  Hillman S.K.,  National Athletic Trainer's Association position statement: fluid replacement for athletes. J Athl Train (2000) 35 : pp 212-224.   • American College of Sports Medicine Position Stand: Exercise and Fluid Replacement. Med Sci Sports Exerc. 377-389, 2007.