Foods and Fuels - 2 and H 2 O Any excess energy in the body...

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Foods and Fuels The energy released when 1 gram of material is combusted is called its fuel value Note: since all heats of combustion are exothermic it is customary to leave off the negative sign when reporting fuel values. Foods Most of the energy our body needs comes from fats and carbohydrates. Carbohydrates are broken down in the intestines to glucose. Glucose is transported in the blood to cells where it is oxidized to produce CO 2 , H 2 O and energy: C 6 H 12 O 6 ( s )+6O 2 ( g ) -> 6CO 2 ( g )+6H 2 O( l ) rxn =-2816 kJ The breakdown of fats also produces CO
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Unformatted text preview: 2 and H 2 O Any excess energy in the body is stored as fats • Insoluble in water so they can be separated and stored in the body • They produce more energy per gram than carbohydrates or proteins Compound Fuel Value (kJ/gram) Fats 38 Carbohydrates 17 Proteins 17 About 100 kJ per kilogram of body weight per day is required to keep the body functioning at a minimum level Exercise • Light exercise burns up about 800 kJ/hour of energy • Heavy exercise burns up about 2000 kJ/hour...
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