Determining Your Daily Calorie Requirement

There are countless diets and nutritional concepts, but the equation for weight loss always remains the same: The calorie consumption must be higher than the caloric intake. Therefore, It is important to know how high the daily calorie requirement is, on the other hand, how many calories you eat. Only, someone who deals with this subject and has an understanding of the needs of his body on the one hand, and on the other hand the nutritional values of the food, has a chance to lose weight permanently. That sounds simple and obvious too, however, most people rely on ready-made diet plans or simple slimming cures that are indeed implemented quickly and easily but hardly promises lasting success.

It is worthwhile to have an understanding of calorie intake and calorie consumption. To achieve a negative energy balance, two screws can be rotated: on the nutrition and physical activity. But first, it is important to find out how high the daily energy requirement is.

Determining your energy demand

The energy needs of a human being are made up of two components: the basal metabolic rate and active metabolic rate. The basal metabolic rate is the amount of energy needed by the body per day at complete rest to maintain the body functions.

The basal metabolic rate of a person is highly individual and depends not only on weight and height but also age, gender, muscle mass, health (eg fever) and the insulation (eg clothing). An exact determination of the personal basal metabolism is achieved by the so-called calorimetry either by measuring the amount of heat emitted (direct calorimetry) or by measuring the oxygen consumption (indirect calorimetry). However, the methods of calorimetry extremely complicated and therefore outside of scientific research are not suitable for everyday use.

Instead, there are different calculation methods. A recent formula for determining the basal metabolic rate in 1990 proposed by Mifflin and St.Jeor [1], takes into account the body weight and height, the age and sex of the person.

The formula for men is:

BMR (men): 10 * (kg) + 6.25 * (cm) – 5 * Age (y) + 5

A 30-year-old man weighing 80 kg with a size of 180 cm would therefore have a basal metabolic rate of (10 * (80 kg) + 6.25 * (180 cm) – 5 * (30 years) + 5 = 800 + 1125-150 + 5) = 1,770 calories .

The formula for women is:

BMR (women): 10 * (kg) + 6.25 * (cm) – 5 * Age (y) – 161

A 27-year-old 65 kg heavy woman with a size of 170 cm would therefore have a basal metabolic rate of (10 * (65 kg) + 6.25 * (170 cm) – 5 * (27 years) – 161 = 650 + 1062.5 – 135 – Size 161) = 1416.5 calories .

Both formulas are almost identical, except for the difference of the last term (+5 for men and -161 in women).

As the BMR estimate the caloric needs of the body at complete rest, to determine the total daily calorie requirement of a normal person, the amount of energy consumed through physical activity must be added. Please note: the more you move, the more energy is converted and the higher the power dissipation. The total energy demand can be estimated by the previously determined BMR multiplied by an activity factor.

Extent of muscular work

very low BMR * 1.2 Just sitting or lying
light BMR * 1.375 Almost exclusively sitting with little or no physical activity
moderate BMR * 1.55 Mostly sitting, with interim additional standing / walking activities
heavy BMR * 1.725 Mostly standing / stop action / regular exercises
very heavy BMR * 1.9 Physically demanding occupation / hard workout (construction workers, farmers, miners, forest workers, athletes)

Let’s return to the example of the above-calculated values for the basal metabolic rate of a man. This was 1,770 calories. If he performs moderate muscular work, his BMR must be multiplied by 1.55 to obtain how many calories he needs daily. His average daily total energy consumption is 1.55 x 1770 kcal = 2743.5 calories.

You do not have to make these calculations by yourself. There are online calculators that you can use to determine how many calories your body needs daily. The calculator from [2] does perfectly the job and even tell you how many calories you need to reduce to lose weight.


1- A new predictive equation for resting energy expenditure in healthy individuals

2- Calculating How Many Calories You Need to Eat Daily to Lose Weight