The energy requirement or calorie requirement is made up of the basal metabolic rate and the turnover and varies from person to person. We have an increased energy requirement in case of stress, fever and hyperthyroidism, as well as women during pregnancy and breastfeeding - in old age and in mental disorders, the need is reduced. Another factor is climatic influences. So in high cold or heat the calorie requirement is also increased.
Basal metabolic rate is the daily amount of energy necessary to maintain all bodily functions (breathing, heartbeat, muscular activity, etc.) at rest for a period of 24 hours. It is about 60 to 70% of the total calorie requirement. During sleep, it drops by 10%.
The basal metabolic rate depends on age, height, gender and weight. The higher the body weight, the higher the basal metabolic rate. However, fatty tissue consumes much less energy than, for example, muscles. So, if you do sports, you have the advantage, because the bigger the percentage of muscle mass, the higher the basal metabolic rate.
For the calculation of the basal metabolic rate - as the exact determination of fat and muscle mass is difficult - mostly the body weight is used.
The turnover is mainly determined by the physical activity at work and leisure time. The caloric expenditure by physical activity amounts to approximately 20 to 30% of the total calorie consumption.
The power turnover is today often determined using the so-called PAL values - Physical Acitvity Level. The PAL depends on the type and duration of professional or sports activities:
|Very low||Only sitting or lying down, for instance when ill or in old age.||1.2|
|Light||Only sitting with less or no physical exertion, for example screen work, without sporty compensation.||1.4-1.5|
|normal||Seated activities, going or standing in the meantime, for example motorists.||1.6-1.7|
|Moderate||Predominantly walking and standing activities, for example salesmen, waiters, craftsmen, housewives.||1.8-1.9|
|Heavy||Physically demanding activities, such as construction workers, competitive athletes, farmers.||2.0-2.4|
In order to maintain the body weight, food must be supplied with the individually required amount of energy. If this value is exceeded in the longer term, it can be expected that the body will accumulate the excess energy in the form of flab.
Calculation of the energy requirement
To calculate your calorie requirement, there is an interactive energy demand calculator from the University of Hohenheim.