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Sports Nutrition. Topics Covered. Carbs to Go and Keep Going Protein to Promote Training Time-Out for a Drink Nutrition Before and During Exercise Nutrition for Recovery Supplemental Strategies. Simple Sugars Complex Carbs Quick and Slow Carbs Stored Glucose and Glycogen Bonking.
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Topics Covered • Carbs to Go and Keep Going • Protein to Promote Training • Time-Out for a Drink • Nutrition Before and During Exercise • Nutrition for Recovery • Supplemental Strategies
Simple Sugars Complex Carbs Quick and Slow Carbs Stored Glucose and Glycogen Bonking Carbs for Daily Recovery Getting Carbo-Loaded Are Carbs Fattening? Foods Highest in Carbs Counting Carbs CHO vs FAT: A Delicate Balance Carbs to Go and Keep Going
Carbohydrates are the primary energy source during exercise • High intensity, short duration (sprint) • > 70% VO2max • Anaerobic pathway produces ATP • Muscle glycogen breaks down into glucose for fuel
Recommended Training Diet • CHO-rich diet + rest days • 60-70% CHO • Choose complex over simple CHOs (unless recovery diet)
Simple Sugars Monosaccharides: 1. Glucose 2. Fructose 3. Galactose
Simple Sugars Disaccharides: Common Name Combination Of... 1. Sucrose Table Sugar (Glucose + Fructose) 2. Lactose Milk Sugar (Glucose + Galactose 3. Corn Syrup (Glucose + Fructose) 4. Maltose Malt Sugar (Glucose + Glucose)
Glucose Polymer • A chain of 5 glucose molecules • More energy with less sweetness
Complex Carbohydrates Complex carbs, such as starch in plant foods and glycogen in muscles, are formed when sugars link together to form long, complex chains, similar to a string of pearls. They can be symbolized like this:
Plants store extra sugars in the form of starch Vegetables (i.e., corn) convert extra sugar into starch • Sweet when it’s young • Becomes starchy as it get older Fruits (i.e., banana) convert starches into sugar • Green w/some yellow: 80% starch, 7% sugar • Mostly yellow: 25% starch, 65% sugar • Spotted/speckled: 5% starch, 90% sugar
Complex Carbohydrates • Get digested into glucose • Either burned for energy • Or stored for future use as • muscle glycogen • liver glycogen
The Glycemic Response – food’s ability to contribute glucose to the bloodstream High Glycemic-Index CHOs • quickly enter the blood stream • best to eat during or after • exercise • ex. Potato, corn flakes, honey Low to Moderate Glycemic-Index CHOs • slowly enter bloodstream • desirable prior to exercise bec. Provide sustained energy • ex. Rice, banana, apple
HIGH MODERATE LOW Glycemic Index of Some Popular Foods
Muscle glycogen Liver glycogen Blood glucose Total: 1,400 calories 400 calories 80 calories 1,800 calories Stored Glucose & Glycogen The average 150-pound male has about 1,800-2000 calories of CHO’s stored in the body:
Muscle Glycogen Storage Muscle glycogen per 100g (3.5 oz) of muscle: Untrained Muscle 13 grams Trained Muscle 32 grams Carbo-Loaded 35-40 grams Well-trained muscles develop the ability to store about 20-50% more glycogen than untrained muscles. (Costill et al. Am J Clin Nutr 34: 1831-1836) (Sherman et al. Intl J Sports Med 2: 114-118)
Pre-Exercise Food Lentils Glucose Water Potato Minutes of Exercise 117 108 99 97 Does the Glycemic Effect of a Food Really Influence Exercise Performance? Cyclists ate 0.5g CHO / lb Thomas, Brotherhood and Brand.1991 Intl J Sports Med, 12 (2): 180-186
Bonking Depleted MUSCLE glycogen “hit the wall” Depleted LIVER glycogen “bonk” or “crash” (no blood glucose) Despite adequate muscle glycogen, an athlete may feel: • Uncoordinated • Light-headed • Unable to concentrate • Weak
John, a 28-year-old runner and banker, faithfully carbo-loaded his muscles for three days prior to his first Boston Marathon • On the evening before the marathon, he ate dinner at 5:00, then went to bed at 8:30 to ensure himself a good night’s rest • As often happens with anxious athletes, he tossed and turned all night (which burned off a significant amount of calories), • John woke up early the next morning, and chose not to eat breakfast, even though the marathon didn’t start until noon • By noon, he had depleted his limited liver glycogen stores • He lost his mental drive 8 miles into the race, and quit at 12 miles • His muscles were well-fueled, but that energy was unavailable to his brain, so he lacked the mental stamina to endure the marathon.
For 3 consecutive days Subjects ran hard 10 miles Pace: 6-8 min/mile Ate their standard meals 45-50% CHO Subjects’ muscles became progressively glycogen depleted CONCLUSIONS Daily CHO rich diet Rest days required to replete depleted muscles Glycogen depletion occurs with repeated days of exercise when CHO intake is inadequate (45-50%)
Glycogen depletion occurs with repeated days of exercise when CHO intake is inadequate (45-50%) 0.5 1.0 1.5 2.0 2.5 Muscleglycogen (gm/100 gm tissue) Costill, Bowers, Branam, et al., J Appl Physiol 31:834-838
Pat, a 33-year-old computer programmer experiments with her 2-hour Sunday run:
Rest and Athletic Performance • Forget to rest? Then, risk the following: • injuries • chronic glycogen depletion • chronic fatigue • reduced performance
Getting Carbo-Loaded • 55 to 65% cho is appropriate • Too much causes intestinal distress • 4 grams per pound or 9 grams per kg • Taper exercise and eat complex carbs the day before the event and a regular breakfast to keep blood glucose levels high
7 days before a race • Taper workouts by 50 % every second day (allows muscle glycogen to maximize) • Also cut back on calories (less output)
6-5 days before a race/event • Eat a variety of complex carbs • Continue to reduce intake • Eat frequently 2-4 hours • Avoid stuffing yourself (excess=fat)
4 day to go • Critical days to top up glycogen • Include bread and grains with meals and eat fruit and fruit juices • Be sure to include protein but watch fat
3 days to go • Training should be minimal • You should start to feel slightly sluggish but relax the extra weight is glycogen (remember it is stored with water) • Expect to gain 2-6 pounds of water/glycogen weight)
2 days left • Fluids, fluids, fluids (using it to pack in glycogen) • A few salty foods to up electrolytes • 2.5-4 litres of water/day
The day before • No training • Small frequent meals (graze on complex carbo’s) No huge meals • Avoid gassy foods/irritating foods • No new foods
RACE DAY ! • Eat a light breakfast (keeps blood glucose up) 2-3 hours before race • Drink consistently 1-2 cups per hour before • If hungry nibble easily digestible foods ie. Crackers, sports bar
Fats: 36 cals/ tsp Body stores fat Metabolic cost of converting excess dietary fat into stored fat = 3% of ingested calories CHO: 16 cals/ tsp CHO: energy first Metaboic cost of converting excess CHOs to fat = 23% Are CHOs Fattening? CHOs are not fattening, excess calories are!
1. Less fattening than fatty foods 2. Muscle fuel 3. Primary fuel during exercise Remember this about CHOs
Foods Highest In CHOs Jim, a 19-year-old college student, intended to carbo-load the night before the Newport Marathon. Due to inadequate nutrition knowledge, he “carbo-loaded” with a pizza supreme. Little did he know that of the 1,800 calories in the large pizza, 1,200 were from the protein and fat in the double cheese, sausage, and pepperoni. Only 35% of the calories from the thin crust and tomato sauce were from CHOs. No wonder he felt sluggish during the race!
Counting Carbohydrates • Your diet: At least 60% CHO for daily training • 65-70% CHO before an endurance event • A high-CHO diet should include some fat! • Fill up with CHO then add fat
Protein to Promote Training How Much Protein Do You Need? Protein and the Vegetarian Protein Supplements and Amino Acids
The BEST sports diet contains: • ADEQUATE, but not excess protein to • build and repair muscle tissue • grow hair and fingernails • produce hormones • boost your immune system • replace red blood cells
Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders • 22-year old men • Lifted weights for 90 min/day, 6 d/wk • Req’d 0.7g pro/lb body weight to stay in protein balance • Example: • 150 lb. Man • Needs 102 g of protein per day Lemon, et al. 1992 J Appl Physiol 73: 767-775
Calculating YOUR Protein Needs • Identify which category you fit into • Multiply your body weight by the range • Example: • 170 lb. Competitive athlete, adult • 170 lb x 0.6 g/lb = 102 g/pro • 170 lb x 0.9 g/lb = 153 g/pro • 130 lb. Competitive athlete, adult • 130 lb x 0.6 g/lb = 78 g/pro • 130 lb x 0.9 g/lb = 117 g/pro
Healthfully Including Meat in Your Diet • Buy extra-lean cuts of beef, pork, and lamb to reduce your intake of saturated fats • Decrease extra fat • Drain meat in a colander • Pat dry with a paper towel • Use meat as the accompaniment to a meal
Too Much Protein • If you fill up with PRO, you won’t fuel your muscles with CHOs • Excess PRO increased urination • Frequent bathroom trips may be inconvenient • Increased risk for dehydration • Extra work for kidneys • $$ Animal proteins tend to be expensive $$ • A high PRO diet tends to be high in fat
Protein Supplements and Amino Acids • Exercise, not protein, is the key to developing bigger muscles • Beware of extra fat • Expensive muscle-building supplements are not the answer
Nutrition Before and During Exercise Guidelines for the Pre-Exercise Meal Timing Meals Before Events Carbo-Loading for Endurance Exercise GI Issues Athletes with Diabetes