Energy is needed by the body to stay alive, grow, keep warm and move around. Energy is provided by food and drink. It comes from the fat, carbohydrate, protein and alcohol the diet contains. Energy requirements vary from one individual to the next, depending on factors such as age, sex, body composition and physical activity level. Energy expenditure is the sum of the basal metabolic rate (the amount of energy expended while at complete rest), the thermic effect of food (TEF, the energy required to digest and absorb food) and the energy expended in physical activity. To maintain body weight, it is necessary to balance the energy derived from food with that expended in physical activity. To lose weight, energy expenditure must exceed intake, and to gain weight, energy intake must exceed expenditure.
Meeting energy needs is the first nutritional priority for athletes. A healthy diet contains the right proportions of carbohydrate (CHO), fat, protein, vitamins and minerals. Carbohydrates and fats are the major sources of energy although energy can be obtained from protein. Energy is measured in Kilocalories (kcal) or Kilojoules (kJ): 1kcal = 4.2 kJ. 1g of Carbohydrates contains 3.75 kcal (16kJ)
1g of Fat contains 9 kcal (37kJ)
1g of Protein contains 4 kcal (17 kJ)
The amount of food we eat (energy intake) should match energy expenditure. If this is the case then we should neither gain nor lose weight as we are in energy balance. If there is inadequate energy intake relative to energy expenditure, the body will use fat and lean tissue mass for fuel. Loss of muscle results in reductions in strength and endurance capacity. Total daily energy expenditure is influenced by heredity, age, sex, body size, fat-free mass, environmental factors, pregnancy and the intensity, frequency and duration of exercise. It is generally made up of three components: 1. Resting Metabolic Rate. This is divided into Basal Metabolic rate (BMR) which is the minimum energy requirement to...
Please join StudyMode to read the full document