Energy Calculator

Food energy is the amount of energy obtained from food and it is usually expressed in food calories (kcal).

The daily energy intake recommended for young adult men and women is 2,500-2,700 and 2,000-2,200 kcal, respectively. Children, those with sedentary lifestyles, and older people require less energy; physically active people more. According to the Food and Agriculture Organization of the United Nations, the average minimum energy requirement per person per day is about 1,800 kcal. (source: http://en.wikipedia.org/wiki/Food_energy)

The largest (about 70%) component of total caloric expenditure is usually the so-called Basal Metabolic Rate (BMR). This is the amount of energy expended daily by humans at rest in order to maintain their temperature and other internal processes. Another 10% (aproximatelly) of the energy expenditure comes from thermogenesis, or digestion of food (postprandial thermogenesis) and the rest comes from physical activity.

The BMR of any individual human can be measured quite accurately by various methods including gas analysis and calorimetry but can also be roughly estimated via appropriate approximation equations using age, sex, height, and weight. The latter is the method used in Food Exchange Diet Planner.

The amount of energy that is spent on thermogenesis is usually considered a constant percentage of BMR. In Food Exchange Diet planner, this constant percentage defaults to 10% but can be easily changed in the formula for the computation of total energy requirements which can be found in the "configuration of advanced parameters" dialog box.

Last but not least, the physical activity level can be entered manually or chosen from a predefined set of activity levels ranging from very light activity (i.e. lying on a bed all day) to very heavy activity (i.e. an athlete exescising twice a day).

Activity Activity factor
Little or no activity 1.1 E.g., almost no activity or exercise
Light activity 1.275 E.g., exercise once or twice a week
Moderate activity E.g., exercise 3-5 days per week
Heavy activity 1.625 E.g., daily exercise
Very heavy activity 1.8 E.g., Exercise twice a day, extra heavy workouts

The following figure displays the energy calculator dialog box.