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Nutrition for Exercise

Nutrition for Exercise. What is Nutrition ?. Science involving study of food and liquid requirements of the body for optimal functioning. Macronutrients Carbohydrates Monosaccardides- Glucose, Fructose, galactose Disaccharides- Sucrose, Lactose, Maltose Polysaccharides Plant Animal

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Nutrition for Exercise

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  1. Nutrition for Exercise

  2. What is Nutrition ? • Science involving study of food and liquid requirements of the body for optimal functioning

  3. Macronutrients Carbohydrates Monosaccardides- Glucose, Fructose, galactose Disaccharides- Sucrose, Lactose, Maltose Polysaccharides Plant Animal Protein Complete Incomplete Lipids Saturated Unsaturated Micronutrients Vitamins Fat Soluble Water Soluble Minerals Essential Trace Water Nutrients

  4. Carbs • Monosacchardides- • Glucose • Fructose • Galactose • Disaccharides • Sucrose • Lactose • Maltose • Polysaccharides • Starch • Fibre

  5. What happened to your breakfast??

  6. Carbs and energy • Glycolisis • Glucogenesis • Gluconeogenesis • Glucogenolysis -Glucose Glycogen- ST storage Energy! (ATP)

  7. Glycaemic Index Index for comparing the blood glucose response from the ingestion of different foods. - The more complex the carbohydrate, and the more fat, proteinand fiber in the food lower glycaemic index.

  8. Note the differences in the area under the curve Whole wheat pasta Glucose Ingestion White bread Note that the blood glucose response to white bread is the standard reference

  9. Proteins • ‘Building blocks’ • Complete- Animal – • Incomplete- plant

  10. Lipids • Saturated • Unsaturated • Monounsaturated • Polyunsaturated

  11. Micronutrients • Vitamins • Vital to release energy from food • Minerals • Important in catabolism and Anabolism of macronutrients • Athletes • Iron, especially for women athletes • Calcium.

  12. Energy for Sport

  13. Major Considerations • CHO & protein requirements • Pre competition meals • Fluid replacement

  14. Normal people 1500—2500 calories 50-60% carbs 20-30% fat 15-20% protein Athletes 1400 (gymnasts) – 6000 (TDF cyclists) 70-80% carbs 20% fats 10% protein Daily intake

  15. RDI’s- Protein • Sedentary people and recreational athletes have similar protein requirements • Sedentary: 0.8 to 1 gram of protein p/kg BM. • Athletes: 1.2-1.8 g protein p/kg BM 87 kg x 1.8 g or 87 kg x 1.2g = 104.4 - 156.6 g p/day 8 28.5 x 2 6 x 2 32 x 2

  16. RDI’s- Carbs • Depends on sport • Normal people: 5 g/kg • Endurance athletes • (training > 60 min p/day: 8-10 g /kg 59 kg x 8 g = 472 g p/day 85 20 75 40 20 40 465 20 17 10 80 45

  17. Preparation for Competition • In general • Taper exercise, 50% CHO diet 1st 3 days • V. low exercise, 80% CHO diet 3 days prior • Strict protocol • Depletion • Day 1- Exhaustive exercise • Day 2,3,4  mod intensity training & low carb intake (100g p/day) • Day 5,6,7  High CHO intake (400-700g)

  18. Bergstrom,Hermansen, Hultman, & Saltin (1967) Mixed diet Low Carb diet High carb diet

  19. Day of Competition Nutrition • 1-4 hours before= Large CHO meal • 150 – 300g carbohydrate (3-5g CHO p/kg BW) OR • 4 hours before – meal (200 g CHO) • 1 hour before- snack (100g CHO)

  20. CHO ingestion every 20 min No CHO ingestion CHO ingestion late in exercise 65-75% VO2max

  21. Liquid Carbohydrate Ingestion • Suited for long duration (> 60 min) exercise where a glucose source is needed to support blood glucose • Need at least 45 g/CHO/Hr • Drink of 60 g CHO/L would require at least 750 mL/Hr • During hot and humid conditions, a lower [CHO] drink would allow greater volumes to be ingested. • Most people can not ingestmore than 1.2 L/Hr • CHO should be mostly glucose

  22. “Hitting the Wall” • Muscle glycogen low • Liver glycogen low • Blood glucose low • Extreme fatigue • Dizziness • Hunger - hypoglycaemia

  23. Post Competition • Depends on time and intensity • 50 - 75 g every 2 hours  500g • Large carbohydrate rich meal • Rest • Rehydrate

  24. Muscle GlycogenSynthesis • Muscle glycogen is synthesized very slowly. The rate of synthesis differs depending on the prior exercise conditions, • after low intensity exercise - 7-9 mmol/kg/Hr • after high intensity exercise - ~ 15 mmol/kg/Hr • Muscle glycogen synthesis is optimized when, • there has been no exercise-induced muscle damage • recovery is passive • at least 0.7 g CHO/kg/Hr is ingested • ingestion occurs as soon after exercise as possible • glucose should be the predominant CHO and the source food should have a high glycemic index

  25. Tour de France riders • Require CHO intake of 13 g/kg BW • Pre competition meal • Breakfast 3 hours before start • High Carb (100g) snack • Energy bars/ energy drinks • 1 hour before start • During the race • Glucose gels- 15g CHO

  26. Liquids - Rehydration • Sweat rates increase with intensity of exercise • Fit people sweat more and sooner; and it is more dilute • Can be up to 1- 2.8 L/hr • Sodium (Na), Potassium (K), Magnesium (Mg), Chlorine (Cl) • Loss of body weight > 3% = danger • Consume 500-1000 ml per hour

  27. Fluids- Gisolfi & Duchman, 1992 • Before: • <1 hr @ 80-130% Vo2max= 300-500ml liquid w/ 30-50g CHO • >1 hr @30-90% Vo2 max= 300-500ml H20 • During • <1 hr @ 80-130% = 500-1000ml H2o • 1-3 hr @60-90% =800-1600ml liquid + 6-8% CHO + Na and Cl • >3 hr = 500-1000ml H20 + 6-8% CHO + NA and Cl • After • Continue H2o consumption • Caffeine, energy drinks and alcohol further dehydrate • Gisolfi, C.V., & Duchman, S.M. (1992). Guidelines for optimal replacement of beverages for different athletic events. Medicine and Science in Sports and Exercise. 24, 679-687.

  28. Gastric emptying Maximal rates of 1-1.2 L /hr with gastric volumes of 100 - 200 mL.

  29. Nutrient and electrolyte content of commercial drinks.

  30. Important nutrients & fads • Female Athlete Triad • Steroid use/abuse • Over-consumption proteins • Muscle building powders • Creatine

  31. Fad Diets • Low CHO • Atkins, Zone, South Beach • Depletes glycogen, “eats” muscle and reduces performance • Relies on ketosis  Bad breath • Starvation • Body conserves fat stores • Lose h20 only • Diet pills • Fat metabolisers do not exist • Placebo effect • Legal action against diet companies

  32. Summary • Sports nutrition has a huge impact on performance • Nutrition and rehydration account for huge gains • Expensive pills, potions and fads account for minute gains if any at all • Avoid fads as many are counterproductive and may be illegal, banned substances

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