Nutrition for Sports and Performance

1. Nutrition for Sports and Performance Ema Thake Sports Nutrition Intern University of Utah

2. Benefits of Physical Activity • Strengthens bones and joints • Reduces blood pressure • Improves blood glucose regulation • Increases cardiovascular function • Aids in weight loss/control • Increases muscle mass/strength • Slows aging process • Improves sleep habits • Improves immune function • And the list goes on…

3. 2008 Physical Activity Guidelines for Americans • 150 minutes/week of moderate –intensity or 75 minutes/week of vigorous-intensity aerobic exercise • Additional health benefits are gained by engaging in physical activity beyond this amount • Perform muscle-strengthening activities that involve all major muscle groups • 2 or more days a week

4. Types of Exercise • Aerobic – with oxygen • Endurance activities • Anaerobic – without oxygen • Short duration, high intensity activities

5. Nutritional Goals • To consume food and beverages appropriate to delay fatigue during training and competition • To consume enough fluid to minimize dehydration during physical activity • Use strategies that are known to be beneficial for performance • Fueling prior to exercise • Fueling during exercise

6. Healthful Diet • Appropriate combination of energy and nutrients • Nutrient dense food and beverages • Provides vitamins and minerals with relatively few calories • Dietary fiber • Whole foods are all nutrient dense when prepared without fats and sugars

7. Basic Guidelines for Sports Nutrition • Energy Intake: • Energy required to maintain energy balance • Adjustments made to energy intake • Carbohydrate Intake: • 6-10 grams/kg/day depending on sport, gender, and training • Appropriate timing of carbohydrate intake • Protein Intake: • 1.2-1.7 grams/kg/day depending on sport, gender, and training • Appropriate timing of protein intake • Fat Intake: • Typically 1.0-2.0 grams/kg/day (25-30% total calories) • Emphasis on healthy fats

8. Basic Guidelines for Sports Nutrition • Vitamins and Mineral Intake: • Meet the DRI • Intake of nutrient dense foods • Fluid Intake: • Match fluid replacement with fluid loss • Other: • Maintain an appropriate body composition • Practice healthy weight loss practices • Avoid disordered eating patterns

9. Energy for Physically Active Bodies • ATP • High energy compound generated via carbohydrate, protein, and fat catabolism • Chemical energy • Used by cells for muscle contractions • Only small amount is stored in resting cells • 2-4 seconds worth of work • Other sources of energy are needed

10. Glycogen • Temporary storage of glucose in liver and muscle • Muscle glycogen • Used only by that muscle • Liver glycogen • Released into bloodstream • “Bonking” or “Hitting the wall” • Depleted glycogen

11. Energy Systems • Three energy systems used in ATP production: • Creatine Phosphate • Anaerobic Glycolysis • Oxidative Phosphorylation • Each system depends on the intensity and duration of the activity • Each systems determines what substrate is used for the activity (i.e. creatine, carbohydrate, fat or protein) • Although one system predominates for specific activities, all three systems are used to some extent at all times.

12. Creatine Phosphate System • Substrate used is creatine • System lasts approx. 5-10 seconds and is anaerobic • Short, fast sprints • 100 m sprint • Short, powerful bursts of energy • Shot punt • Dunking a basketball • Activities requiring large amounts of force • Heavy weight lifting

13. Anaerobic Glycolysis • Substrate is carbohydrate • Lasts approx. 1-2 minutes and is anaerobic • Sustained sprints • 400m • Repeated high intensity sprints • Soccer • Basketball • Repeated high force activities • 10-15 reps of lifting weights • Regular, repeated intervals • 50-100m swimming intervals

14. Oxidative Phosphorylation • Can use carbohydrate, fat and protein as substrates • Occurs in the mitochondria • Aerobic • Long lasting energy system • Fatigue associated with glycogen depletion

15. Substrate Utilization • Carbohydrate and fat are preferred energy sources • Protein is the least desirable energy source • Fat is primary source at rest (85%) • Carbohydrate is primary source for moderate to hard exercise • As exercise intensity increases, % energy from fat decreases • Respiratory exchange ratio (RER) can be used to determine the proportion of carbohydrate to fat being oxidized. • Ratio of O2 consumed to CO2 produced

16. RER for Carbohydrate

17. RER for Fat

19. Carbohydrate, Fat, and Protein Metabolism • In fed state: • Glucose is used for immediate energy • Extra glucose is stored as glycogen for future use • Fat is stored for future use • Non-fed state: • Glycogen from the liver is broken down to provide glucose • Fat is released from storage and used as energy source

20. Carbohydrate • ~60% of total kcal from carbohydrate • Variety of foods important • Whole grains • Fruits • Vegetables

21. Carbohydrate and Exercise • Primary fuel for exercise • Stored as glycogen: • Muscle glycogen • Liver glycogen • Amount of stored glycogen is dependent on diet and training • Stores must be replenished daily • Glycogen depletion leads to muscle fatigue • > 5 gm of carbohydrate/kg body weight • Minimum amount needed to replenish stores • Aerobic and endurance athletes • 7-10 gm carbohydrates/kg body weight

23. Carbohydrate Before Exercise • Pre-exercise meal should be low in fat and fiber, high in carbohydrate, moderate in protein • 1 gram/kg/hour prior to exercise • Ex: 2 hours before exercise, eat 2 grams/kg of carbohydrate • Recommended to consume carbohydrate AT LEAST 3-5 hours before exercise • Always recommended if no access to CHO during exercise

24. Pre-Exercise • Snacks (1-2 hrs prior): • Jelly on whole wheat bread • Milk and cereal • Yogurt with fruit • Meals (3-5 hrs prior): • Pasta with marinara sauce, green beans and low fat milk • A muffin and fruit smoothie • Turkey sandwich with whole wheat bread and orange juice

25. Carbohydrate During Exercise • Beneficial for endurance activities lasting > 60 minutes • Delays fatigue and time to exhaustion by sparing and maintaining adequate glycogen stores • Recommended 45-60 grams CHO per hour after the first hour of exercise • Can be in the form of food or sports drinks

26. Carbohydrate After Exercise • Ideal environment for restoring glycogen • Greatest amount of resynthesis occurs in the first hour after exercise • Recommendations: • Consume 50-70 grams of CHO as soon as possible after exercise • Small, frequent CHO containing meals • Addition of protein

27. Post-Exercise Snacks • Cottage cheese with fruit • Bagel with peanut butter • Chocolate milk • Crackers and cheese • ½ sandwich with turkey or peanut butter

28. Carbohydrate Loading • Not beneficial in events < 60-90 minutes • Can postpone fatigue by 20% • Goal is to maximize glycogen stores • Tapering of exercise while increasing carbohydrate intake

29. Fat • Provides energy at rest and during low intensity exercise • More energy dense than carbohydrate or protein • 9 kcal/gram • ~35% of total kcal is appropriate for general population

30. Fat • Diet should be rich in monounsaturated and polyunsaturated fats • Avocado • Olive oil • Nuts • Limit saturated fats • Lard • Butter and cream • Coconut oil • Limit trans fat • Grilling and steaming are preparation methods that do not require additional fat

31. Protein • Tissue growth, hormones, enzyme, and immune system response • Found in both plant and animal foods • Animal proteins = complete protein • Plant proteins = incomplete proteins • Exception is quinoa • Needs are easily met by a normal diet • Protein supplements are not necessary • Excessive protein has not been shown to be beneficial • NOT preferred energy source during exercise

32. Protein and Exercise • Prolonged endurance exercise results in catabolism of some protein for energy • Recommend 0.8 - 1.7 gm protein/kg body weight • Up to 2.0 gm/km body weight for athletes beginning strength training

34. Protein Intake Post-Exercise • Take advantage of the “anabolic window” • 10-20 grams within 30-60 minutes of completing exercise • Post-exercise snacks should also include 50-70 grams of carbohydrate • Cottage cheese with fruit • Bagel with peanut butter • Chocolate milk • Crackers and cheese • ½ sandwich with turkey or peanut butter

35. Fluids and Electrolytes • Water is an essential nutrient • Excessive water loss could be detrimental to performance and health • Important to maintain body water • Average 42 L for males • Average 30 L for females • Tissues containing body water: • Muscle – 75.6% water • Liver – 68.3% water

37. Fluid Balance and Imbalance • Euhydration • Under normal conditions, water balance maintained • Hyperhydration • Kidneys respond by increasing urine output • Drinking large amounts • Cause cells to swell and function is impaired • Hypohydration • Body fluid below normal levels • Inadequate intake, excessive loss or both • Cells shrink and function is impaired • Affects thermoregulation --- performance and health

38. Fluid and Exercise • Fluid balance easily regulated under normal conditions • Exercise disrupts fluid balance • Increases body temperature • Increases fluid loss via sweating • Becomes difficult to match fluid intake with fluid loss • Fluid replacement during exercise can be difficult • Dehydration due to inaccurate thirst mechanism • Rate of absorption is limited • Performance suffers when fluid losses equal 2% body weight

39. Electrolytes • Important for maintaining hydration • Balance regulated by the renal system • Lost in large amounts via sweat during exercise • Sodium increases voluntary fluid intake and increases fluid absorption • Sources: • Food • Beverages • Salt tablets – insufficient evidence regarding exercise

40. Assessing Hydration • Weight loss during exercise • Weigh before and after • Thirst • Urine color

41. Symptoms of Dehydration

42. Fluid Replacement • Prior to Exercise: • Adequate hydration • 5-7 ml/kg at least 4 hours prior to exercise if adequately hydrated • During Exercise: • Goal is to replace fluid lost and maintain fluid balance • After Exercise: • 150-200% • 2-3 cups for every pound lost • 1.5 L for each kg body weight lost

43. Sports Drinks • Appropriate for exercise lasting > 60 to 90 minutes • Contains carbohydrate and electrolytes • Sodium • Potassium • Chloride • Enhances absorption due to sugar and sodium content

44. Hyponatremia • Extremely low plasma sodium concentrations (<135 mmol/L) • Symptoms similar to dehydration • Confusion, seizures, coma, death • Prevention: • Avoid overconsuming water during exercise • Replace sodium that is lost in sweat

45. Vitamins and Minerals • Fat soluble • ADEK • Absorbed into lymph • Stored in liver and adipose • Deficiencies slow to develop, toxicity more likely • Daily intake not critical • Water soluble • B vitamins and vitamin C • Dissolve in water • Absorbed into bloodstream • Excess excreted in the urine • Deficiencies rapid to develop, toxicity less likley • Daily intake important

46. Vitamins and Exercise • Factors that increase needs: • Increased loss in sweat or urine • Decreased absorption • Increased enzymes used in protein synthesis • Factors that decrease needs: • Decreased urine excretion • More effective recycling (vitamin C)

47. Vitamins and Exercise • Vitamins are essential for biochemical pathways in the body • Athletes can easily reach DRI by consuming whole foods • Supplementation not necessary unless deficiency is present

48. Questions? Thank you!

49. Resources • Dunford M and J. Andrew Doyle. Nutrition for Sport and Exercise. • Gordon M. Wardlaw, Anne M. Smith, Angela L. Collene. Contemporary Nutrition: A Functional Approach. Third Edition.