Note Final Exam-please check final schedule

Nutrition 265-Fall 2011- Principles of Nutrition in Human Metabolism Note Nutrition 265-Fall 2011- Principles of Nutrition in Human Metabolism Nutrition 205-Nutritional Assessment-Theory-Fall 2011 Nutrition 207- Nutritional Assessment-Application- Winter 2012 or Nutrition 201-Sports Nutrition-Winter 2012-pending pending approval of 201

Nutrition and Exercise Lecture 31- 21 March 2011   Nutrition and Exercise

Carbohydrate and fat produce most of energy for exercise  

Carbohydrate Intake before competition Increase intake by up to 10 grams per kg bw per day for about 3 days before competition   -this loads the muscle with glycogen -weight gain is inevitable because each gram of glycogen is stored with about 3 grams of water

Everyday exercise-before exercise   -not necessary to increase carbohydrate to extent above -however need sufficient carbohydrates to burn fat -take some carbohydrate in solution – easier to get a rise in blood sugar -timing is important- take about 3 hours before exercise which allows insulin to do its work and avoid low blood sugar

Carbohydrate intake during exercise   -usually 2 hours maximum before run out of carbohydrate available for body functions requiring carbohydrate during exercise -for average exerciser this is not a problem

Carbohydrate intake during exercise -for high intensity athletes the 2 hour limit poses a problem -sports drinks containing sucrose, fructose or glucose polymers are a choice   -many athletes prefer glucose polymers since they are as sweet as simple sugars -6-10 % carbohydrate solution at 500-1500 ml/hour is appropriate for athletes exceeding the 2 hour limit

Carbohydrate intake after exercise   -muscle glycogen restored within 24 hours post-exercise if diet is carbohydrate rich -50 grams of carbohydrate every two hours -athletes competing in multi-event tournaments- every effort should be made to consume plenty of carbohydrate before the next event even if this means eating empty kcal foods

Carbohydrate intake after exercise -most athletes need 500-800 g of carbohydrate everyday to maintain optimal glycogen stores   -high glycemic index foods if between athletic events or between periods -a high glycemic index food is one where carbohydrate in food is quickly converted by body to glucose -eg of high glycemic index foods (bagel, bread, honey, baked potato)

Carbohydrate intake after exercise -moderate to low glycemic index foods are appropriate prior to prolonged exercise (marathon or hike)   -eg of moderate glycemic index foods oatmeal and rice -eg of low glycemic index foods -apples, peaches, pears

Lipid and Protein -a lot of protein or fat before exercise is not helpful -fat makes one feel uncomfortable   -protein should not be relied upon as the primary fuel -no more than 30 % of calories from fat and 10-15 % of calories from protein

Protein supplements Waste of money-Why?   Get enough protein if just increase calories Need increased calories to meet increased energy output Therefore if eat in accordance with adequacy, balance, energy control, nutrient density, moderation and variety one should have enough protein to meet one’s protein needs for exercise

Athletes use 25- 50 % more calories than non-athletes   -2500-6000 kcal per day in training -athletes should minimise lean body mass losses (muscle) -other proteins are lost when lean body mass is lost- eg enzymes -any combination of increased caloric expenditure and reduced caloric intake should not exceed 1000 kcal

Vitamins and minerals   -as increase energy intake and assuming one continues to follow the principles of adequacy, balance energy control, nutrient density, moderation and variety one should have enough vitamins and minerals to meet one’s vitamins and minerals needs for exercise -supplements do not enhance performance- good nutrition does enhance performance

Vitamin supplements Generally if one follows Canada four food groups and eats according to the principles of adequacy, balance, variety nutrient density, calorie control and moderation one will not need vitamin supplements  

Water   -adequate fluid balance is critical- all metabolic functions depend on water -increased demand for fluid due to increased fluid losses (sweat, respiration)