Our bodies require a certain amount of body fuel (calories from food) each day to function. This amount of body fuel is determined by 2 factors:
Physical Activity and Basal Metabolic Rate (BMR).
Physical Activity – the amount of fuel (calories) used by our bodies for physical activity depends on the intensity and duration of the activity as well physiological factors such as our gender, size and muscle mass. Generally, the more intense and longer the activity the greater the body fuel required. Put simply – the more active we are the more calories we burn.
Basal Metabolic Rate (BMR) – is the fuel required by our bodies for all normal body functions necessary for our survival even at rest including breathing, healing, pumping of the heart, brain function, maintaining body temperature, digestion and even sleeping.
Our BMR is affected by many things including gender, muscle mass, age, genetics, illness and stress. The BMR of healthy adults can account for 50 – 80% of daily body fuel requirements.