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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 • Glycogen- • Starch- • Fibre

  5. Carbs- The basics • Glucose is a type of monosaccharide that is in the food that we consume • Blood glucose is used to fuel the working muscles • Called glycogen when stored in muscles or the liver

  6. What happened to your breakfast?? • Carbohydrate meal is eaten and digested, • Blood glucose levels rise, and the pancreas secretes insulin • GLYCOGENESIS- glucose converted to glycogen [for ST storage] as long as both insulin and glucose remain plentiful • Blood glucose used for immediate energy requirements • When glucose levels begin to fall, insulin secretion is reduced, and glycogen synthesis stops. • About four hours after a meal glycogen begins to be broken down to be converted again to glucose [GLYCOGENOLYSIS] • For the next 8–12 hours, glucose derived from liver glycogen will be the primary source of blood glucose to be used by the rest of the body for fuel.

  7. Carbs terminology • Glycogenesis = glucose  glycogen • Glycogenolysis = glycogen  glucose • Gluconeogenesis=non CHO sources  glucose • Glycolysis = Glucose  Pyruvic acid Krebs cycle 4 calories of Energy (+ Co2 and H20) 1 gram glucose (+ oxygen)

  8. Storage • LIVER- Only the glycogen stored in the liver can be made accessible to other organs. 100–120 g stored in an adult • MUSCLES- lower concentration (1% of the muscle mass), but the total amount exceeds that in liver. • Small amounts of glycogen are found in the kidneys, and even smaller amounts in certain glialcells in the brain and white blood cells Once muscle glycogen stores are depleted  performance decreases

  9. Glycaemic Index Index for comparing the blood glucose response from the ingestion of different foods. - The more complex the carbohydrate, and the more fat, protein and fibre in the food lower glycaemic index. High = GI>70 Mod = GI 56-70 Low = GI<55 Lower = slower

  10. 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

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

  12. Lipids • Saturated • Unsaturated • Monounsaturated • Polyunsaturated

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

  14. Energy for Sport

  15. Major Considerations • RDI’s - CHO & protein requirements • Pre competition meals • Fluid replacement

  16. Normal people 1500—2500 calories Athletes 1400 (gymnasts) – 6000 (TDF cyclists) Carbohydrate= 55-60% Fats <35% Protein= 10-15% Daily intake

  17. RDI’s- Protein • Sedentary people and recreational athletes have similar protein requirements • Sedentary Adults: 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

  18. RDI’s- Carbs • Depends on sport • Normal people: 5 g/kg • Athletes: 5-13 g /kg depending on training intensity 59 kg x 8 g = 472 g p/day 85 20 75 40 20 40 465 20 17 10 80 45

  19. Preparation for Competition- Carb loading • 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)

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

  21. Day of Competition Nutrition • 1-4 hours before= Large CHO meal • 200-500 calories • 150 – 300g carbohydrate (3-5g CHO p/kg BW) OR • 4 hours before – meal (200 g CHO) • 1 hour before- snack (100g CHO)

  22. Rebound hypoglycaemia • High GI carbohydrate consumed 15-45 min before exercise • it can stimulates insulin secretion •  converts glucose to glycogen and stores it •  low blood glucose levels • Less fuel available for exercise Pg 333 of text

  23. Liquid Carbohydrate Ingestion • Suited for long duration (> 60 min) exercise where a glucose source is needed to support blood glucose • As long as it is consumed late in exercise when muscle glycogen stores are low it will not cause rebound hypoglycaemia • Need at least 45 g/CHO/Hr • During hot and humid conditions, a lower [CHO] drink would allow greater volumes to be ingested. • CHO should be mostly glucose

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

  25. Post Competition • Depends on time and intensity • after low intensity exercise - 7-9 mmol/kg/Hr • after high intensity exercise - ~ 15 mmol/kg/Hr • Important to consume 2 hours post exercise while rate of glycogen synthesis is high • Large carbohydrate rich meal • With some addition protein • Rest • Rehydrate

  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- • 2 hours before: • 400-600 ml fluid • During • 150-350 ml every 15-20 minutes • If > 1 hour- 4-8% CHO plus Na and Cl • After • Continue H2o consumption- thirst not an accurate indicator • 900-1200 ml for every kg lost • Caffeine, energy drinks and alcohol further dehydrate • Recommendations from text box in page 347

  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. Summary • Sports nutrition has a huge impact on performance • Nutrition and rehydration account for huge gains • Need to be careful of rebound hypoglycaemia and gastric emptying • Expensive pills, potions and fads account for minute gains if any at all

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