In our guide for calorie requirements, we are happy to provide answers to the ten most important questions. You can also use our calorie requirement calculator to immediately determine online how high your daily basal metabolic rate, active metabolic rate and total metabolic rate are.
The 10 most important questions about calorie requirements
What are calories?
Calories ensure that the body temperature is maintained and that important metabolic functions are fulfilled. The term calories (cal) is an officially obsolete but still commonly used unit of measurement for the energy content or calorific value of food. For commercial foods, for example, this value is also given in the unit of measurement of joules, which is internationally valid today (1 kcal, i.e. kilocalorie, is equivalent to 4.1868 kJ, i.e. kilojoule). Calories refer to the energy that is released during the burning or digestion of nutrients in the body in order to determine the energy content of nutrients.
What does the calorie requirement depend on?
Our daily calorie requirement is dependent on our individual energy needs. Two parameters determine the calorie requirement of an adult: on the one hand, the basal metabolic rate, which depends on factors such as age, sex, weight or muscle mass, and, on the other hand, the exerted power (activity). Increased exercise or sport can lead to an increased energy requirement.
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What is the basal metabolic rate?
The basal metabolic rate is the amount of energy required daily by the body in a sober state, at complete rest and at a body temperature of 28° to maintain its functions. The basal metabolic rate therefore includes various bodily functions. Energy is used in the body to maintain the function of all organs, the activity of the heart muscle, breathing, muscles and blood flow. Furthermore, the maintenance of the body temperature, for which about 70-80% of the energy is used, is a factor in the basal metabolic rate. In addition, there are the energy requirements of the brain, which controls physical processes and requires energy for thinking. The basal metabolic rate does not take into account the energy consumption of digestion. This value depends on age, sex, height and weight and is calculated using a complex formula called the Harris-Benedict equation.
According to this equation, the following applies for men
Metric: 66.5 + ( 13.75 × weight in kg ) + ( 5 × height in cm ) – ( 6.76 × age in years ) = basal metabolic rate.
Imperial: 66.5 + ( 6.24 × weight in pounds ) + ( 12.7 × height in inches ) – ( 6.76 × age in years ) = basal metabolic rate
The following applies for women
Metric: 655.1 + ( 9.56 × weight in kg ) + ( 1.85 × height in cm ) – ( 4.7 × age in years ) = basal metabolic rate
Imperial: 655.1 + ( 4.34 × weight in pounds ) + ( 4.7 × height in inches ) - ( 4.7 × age in years ) = basal metabolic rate
Calorie Requirement Calculator
What is understood by active metabolic rate?
The term active metabolic rate or working metabolic rate defines the calorie requirement of a body in addition to the basal metabolic rate for work activities. The PAL value (physical activity level) is used to calculate this rate. People who perform physically demanding work or athletes have a higher active metabolic rate and therefore higher calorie requirement than people who are sedentary and do not exercise much.
What does total metabolic rate mean
This value, also called total energy, refers to the total amount of energy consumed by a body every day. It is calculated from the basal metabolic rate plus the active metabolic rate.
How is the calorie requirement calculated?
To calculate the individual calorie requirement, the basal metabolic rate is multiplied by the PAL value for the average activity level of the activities performed. This calculation is based on the average values specified in the guidelines of the German Society for Nutrition (DGE). The basal metabolic rate represents one part of a person's daily calorie requirement. Added to this is the energy consumption due to the diet - food intake increases the energy requirement by approx. 5-7% - as well as other physical performance. Depending on the physical activity, the basal metabolic rate is multiplied by a certain value, e.g., x 1.4 for predominantly sedentary work or x 2 for physically demanding work. The result represents an approximate estimate of the calorie requirement.
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To what extent does the calculation of the calorie requirement help with weight loss?
Our daily intake of calories is often higher than our actual calorie requirement. As a result, we gain weight. On the other hand, we lose weight by burning more calories than we consume. Therefore, in order to lose weight, it is important to find out how many calories you actually need each day. The basis for this is the total energy expenditure, consisting of the individual basal and active metabolic rate as well as the digestive metabolism. In order to lose weight successfully and healthily, it is, on the one hand, necessary to consume a number of calories that exceeds the basal metabolic rate in order to avoid damage to health. On the other hand, the calorie intake, ideally consisting of food rich in vitamins and minerals, should be lower than the total metabolic rate (negative energy balance).
Why do men and women have a different calorie requirement?
Since men have on average more muscle mass, heavier bones and less body fat than women, they have a higher calorie requirement. They burn more calories than women – even at rest during periods of low physical activity. Therefore, men can eat more food than women without gaining weight, and they also lose weight faster.
To what extent does age influence the calorie requirement?
With increasing age, muscle mass usually decreases. At the same time, metabolic functions are optimised, which means that less energy is required with increasing age. However, since this adaptation of the metabolism is very complex and has not been sufficiently researched, values in which age plays a role can only be determined approximately. The Harris-Benedict equation also takes age into account.
How does sport affect the calorie requirement?
Athletic activities are added to the determined calorie requirement. The amount of additional calories required depends on the type of sport, the duration and intensity of exercise.
As source for the information in the 'Calorie requirement' category, we have used in particular:
Last update on November 29, 2022
The pages of the 'Calorie requirement' category were last editorially reviewed by Stefan Banse on November 29, 2022. They all correspond to the current status.
Previous changes on June 25, 2021
- January 1, 2020: Publication of the calorie calculator.
- Editorial revision of all texts in this category