carb loading, glycemic index and glycemic load nelson pe pages 93 and 94, 345 and 347
Post on 28-Dec-2015
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Food Fuel used during exercise and rest.
• Carbohydrates – preferred fuel source during exercise. Contribute about 1/3 of energy at rest.
• Fats – preferred fuel source at rest (contribute 2/3 of energy) . Also used during sub-maximal exercise in addition to carbs.
• Protein – usually used for growth and repair but is used as a last resort if the body is starved of other sources.
Glycemic index
• Glycemic index (GI)- measure how quickly a food releases sugar into the bloodstream.
• Low glycemic index foods are better to eat before physical exercise because the energy last longer.
• Glycemic load – GI x carbohydrates in grams per serving.
Factors that affect GI
• Fatty foods can delay stomach emptying and slow release of sugar into the blood.
• Organic acids can lower GI e.g. vinegar• Physical entrapment of sugars within food.• Type of starch involved.
GI and endurance sports
• Low GI foods should be consumed 45 to 60 minutes before exercise.
• High GI food reduce performance if consumed in this period.
• High GI foods need be consumed immediately before exercise.
Carbohydrate loading
• In sports such as marathons where you exert yourself for long periods without a chance to refuel it carb loading is a strategy used to make sure there is stored carbs available for the body to use.
• Not useful for teams sports where you have a chance to eat and only exert yourself in bursts.
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