to be .2kcal per gram of protein oxidised. The physiological energy values of foods calculated from the gross energy values after allowing for the losses in digestion and metabolism are as follows: Carbohydrates . ;fats . and proteins .
. . Energy Energy is the capacity to do work. Energy must be supplied regularly to meet the needs of the body for survival.
The body needs energy for maintaining body temperature, metabolic activity, supporting growth, for physical work, to maintain constant body weight and good health. . . Energy yielding food factors The energy yielding food factors are (i) carbohydrates (ii) fats and(iii) proteins.
Within the body, these are oxidised in the cells. The process is one of continuous utilization of O and production of CO H O and heat. . .
Units of energy – calorie and joule The energy value of foods can be expressed in terms of kilocalories(KCal) or megajoules(MJ).The International Union of Nutritional Sciences has suggested the use of megajoule as the energy unit in place of Kcal. These units are defined as follows: Kilocalorie: One kilogram calorie is the quantity of heat required to raise the temperature of kg of water through ° C. Joule: A joule is defined as the energy required to move 1kg mass by metre by a force of Newton acting on it. Newton: One Newton is the force needed to accelerate kg mass by less than a second.
Carbbohydrates CO + H O + heat Oxidation and fats Proteins CO + H O + heat +urea Oxidation - - Carbohydrates and Energy (using a Respiration Calorimeter and Metabolic Chamber) or indirectly from O intake and CO expenditure when the subject is at rest. . . Basal Metabolic Rate (BMR) The rate of energy use for metabolism under basal metabolism is usually expressed as kcal/kg body weight per hour.
The factors affecting BMR is presented in table . These values are known as ‘Atwater Bryant factors’ or physiological fuel values. . .
Coefficient of digestibility The coefficient of digestibility is used