BIOENERGETICS AND METABOLISM
Summary of main points.
• Bioenergetics is the study of energetic events occurring in living organisms; it covers energy (food) intake and energy expenditure.
• Fat is the most energy dense nutrient, containing more than twice the energy of carbohydrate or protein. Energy expenditure is made up of resting metabolic rate, the thermic effect of food and the energy cost of physical activity.
• Even very small females require an energy intake of around 1200kcal per day to maintain energy balance.
The living cells of the human body are in a constant state of molecular activity, where they are used, degraded and synthesised to maintain life. These actions require energy which is defined as ‘the capacity to perform work. This definition does not, however, describe the many biological functions that either require or liberate energy in the body.
Understanding what energy is and how the body acquires, converts, stores, and utilises it is the key to understanding how humans can perform activities. It also provides the basis for understanding how fat is used as an energy source, or substrate, and how this may be optimised for best maintenance of body fat levels. The study of energetic events occurring in living organisms, which commenced in the 18th century, is called bioenergetics.
*35\186\4*
