BIOENERGETICS
Energy can take a number of forms: nuclear, light, chemical, electrical, mechanical, thermal, magnetic and potential.
According to the laws of thermodynamics, all forms of energy are interchangeable and energy is neither gained nor lost, it merely changes form. With respect to humans this means that the body cannot create or destroy energy, but it can convert one form of energy to another. Humans use chemical energy from food for synthesis and other metabolic processes. The chemical energy from food is converted to various forms such as mechanical energy which results in movement, chemical energy to make hormones, or electrical energy to conduct nerve impulses. Unless energy is stored in the body, it is eventually lost, mainly as heat (thermo-genesis). Since living organisms are governed by the laws of thermodynamics, an energy balance equation has been used to forecast changes in body mass when changes in energy intake or expenditure occur, although this is not as clear cut as was once thought.
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