Carbohydrates PDF

Learning Outcome. By the end of this chapter, students will be able to: *Learn the relationship between macro nutrient metabolism and exercise intensity and duration. C2, C4 *Carbohydrate loading concept for endurance sports. C2 *Understand the need of macro nutrients pre, during and post activi...

Learning Outcome. By the end of this chapter, students will be able to: *Learn the relationship between macro nutrient metabolism and exercise intensity and duration. C2, C4 *Carbohydrate loading concept for endurance sports. C2 *Understand the need of macro nutrients pre, during and post activity and plan the meals according to the need of the sports. C2, C4, C5, P5 *Recommendations for dietary intake into involvement of vitamins and minerals in disease prevention and good health. C2 *Involvement and impact of dehydration in reduced heat tolerance and fatigue. Recommendations for water consumption during training and competition. C3, C5,P5, A2  Carbohydrates are chemical compounds containing carbon, hydrogen, and oxygen.  Starches (bread, rice, etc.) and sugars are the major types of carbohydrate found in our diets.  While carbohydrates have a variety of specialized functions in the body, their major function is as a source of energy (4 calories/gram) for various body organs and tissues.  This is especially true for the muscles used during exercise.  How much Carbohydrate should be consumed daily?  The quantity of carbohydrates needed on a daily basis varies among athletes based on several factors:  Current body weight  Total energy needs  The specific metabolic demands of their sports  Stage of training or competition schedule.  Carbohydrate requirement distribution range for male and females is 55-65% of daily calories.  Relationship between Current body weight and CHO intake:  CHO intake needs can be determined based on current body weight.  5 – 10grams of CHO per kg of body weight is a general recommendation for athletes.  This method shows clearly that individual CHO needs vary greatly.  An athlete who weighs 60kg requires 300 to600 grams/day versus 90kg athlete whose estimate reaches the range of 450 – 900grams.  The large range in recommendation allows for changes in exercise intensity, environmental conditions, and personal preferences, as well as type and quantity of daily activities.  Athletes who are exercising 3-5 times per week will require amounts at the low of the range.  And athletes who are training 6-7days per week, and with multiple work outs a day, will require CHO at a higher end.  CHO needs be determined based on a percentage of total calories:  For athletes, the higher end of this percentage range is usually recommended.  As training volume increases, or for endurance athletes preparing and tapering for competition, the percentage of CHO can increase beyond the recommendation range as high as 70-75%.  It is important to calculate and compare the grams of CHO based on both current body weight and the percentage of calories coming from CHO.  For example: for a 70kg middle- distance runner who consumes 4000kcal per day, of which 50% are CHO calories, will consume approximately 500grams of CHO.  At 70kg, 500gm is approximately 7 gm per kg body weight.  However, 7gms of CHO per/kg body weight falls within the 5-10g/kg recommendation and both the guidelines are met.  Athletes competing in the Race across particular long distance, a nonstop cycling race from coast to coast, may consume as much as 70-80% of their calories from CHO during the event.  Impact of stage of training or competition schedule on CHO intake:  For athletes CHO needs will increases slightly as training volume increases or when approaching a competition.  During the off season or recovery period, total calorie needs may be lower and the total CHO needs also decline.  During competitive season, CHO needs remain high in preparation for hard workouts or events.  Various Sources of Dietary Carbohydrates:  The richest sources of CHO:  Grains, fruits, vegetables  Milk  Beans, legumes, and nuts  Sweets , desserts, soda  Best CHO choices within grain groups: are complex CHO which contains fiber and B vitamins.  The key to choose these they are more nutrient dense and sustain energy longer than refined CHO.  Best CHO choices with in fruits and vegetable groups:  Soluble and insoluble fiber  Vitamin C, potassium and beta carotene.  Variety of antioxidants and phytochemicals  Best CHO choices within the milk /alternative group: these provides mix of CHO and proteins.  Milk is the good sources of calcium and Vitamin D which is beneficial for athletes participating in weight bearing sports, providing strength and structure to the bones.  Best CHO choices within meat and beans/alternative groups:  Beans, lentils, nuts, seeds and soy products are excellent sources of CHO and also good sources of protein, iron, zinc and fiber.  At rest and during low exercise intensities (2-3 hours prior if possible; ingest CHO 15- 30min prior if desired; hydrate appropriately.  Limitation of Classical Carb loading methods  Difficulty in execution (6 Day protocol)  Physical and mental consequences.  Not in line with the usual regime of athlete  Low dietary CHO phase may increase the risk for injury  Bloating, gastrointestinal (GI) distress,  Higher weight gain during the high CHO phase  Modern Method of Glycogen Loading:  This method entails a tapering down of exercise duration while maintaining the intensity levels at 75% VO2max during the 6 days prior to a competition.  During this time the contribution made by CHO to the energy in the diet increases.  Energy level must be appropriate to balance expenditure.  Benefits of Modified Carbohydrate Loading  Super compensation of the muscle glycogen,  Eliminated the need to perform an exhausting exercise bout within a few days of a competitive event,  Avoided several days of low dietary CHO intake  A reasonable exercise taper  Updated Carbohydrate loading  10-12 g/kg BM per 24 h  3 Days prior to competition  If not possible to follow 3 days at least 24-36 Hour before the competition  Tapering the exercise load over last week  Carbohydrate loading: Practical Aspect  1-2% weight gain post CHO loading (1 g of glycogen is stored in muscle with 3–5 g of water)  Regular weight in to insure the progress in CHO loading.  Suitable food choices and meal plans based on individual tolerance, likings, food availability and schedule.  Athletes should experiment with different meals before training  Practice the CHO loading regimen well before important competitions like during a long training session or a minor event  CHO 3-4 Hours Prior to Exercise: 200-300g of CHO 3-4 hours prior to exercise for an adult maximizes glycogen stores at the onset of exercise and thus enhances performance.  Body size, or more appropriately glycogen storage potential, accounts for the broad range.  This will be appropriate to maximize glycogen stores at the onset of exercise and thus enhances performance.  CHO 30-60minutes before Exercise:  Ingest 50-75g of CHO.  CHO immediately before exercise:  If CHO is to be consumed immediately prior to exercise (