BMR calorie requirement – what is it?

The invention of the BMR index has permanently changed the approach to the role of nutrition in shaping human health. It has provided a tool that makes it easier to adjust the quantity and quality of food consumed to individual needs. Basal metabolic rate, abbreviated as BMR, is a fundamental piece of knowledge about one's body, and everyone should know their estimated BMR, especially since it is not difficult to calculate.

1. What is BMR?
2. Estimating BMR
3. Application of BMR

What is BMR?

The 18th-century French scientist Antoine Lavoisier is considered to be the inventor of BMR. He developed a method for measuring oxygen consumption by the body, which was converted into the metabolic activity level of the person or animal being tested. Together with his wife, they discovered that the air exhaled by animals consists of oxygen from outside and carbon and hydrogen from the animal (more precisely, from the food it consumes).

These are used to produce water, carbon dioxide and heat. Over time, scientists observed that the greater the body mass and energy requirements, the greater the oxygen uptake. They were the first to show that oxygen uptake depends on the number of calories consumed, the ambient temperature and muscle activity. The most important task of this research at the time was to detect abnormalities in the functioning of the thyroid gland.

In the twentieth century, however, with the intensive development of all sciences, BMR came into wider use in both health and medical sciences. Today, this indicator is often referred to as the minimum cost of living, as it is the amount of calories that the body ‘burns’ in a state of undisturbed effort and without stress.

Estimating BMR

After thousands, and perhaps even millions, of people whose gender, age, weight, height, and oxygen consumption were related to BMR values, it was decided that this was the correct indicator of daily basal calorie requirements. At the beginning of the 20th century, the Harris-Benedict formula was developed, which allowed this coefficient to be calculated on the basis of the above-mentioned data.

Nowadays, this value is calculated using easily accessible online calculators, which estimate BMR using principles similar to those used in the Harris-Benedict formula. These calculators usually also take into account a multiplier related to the level of physical activity. After taking into account the average daily duration of exercise, a value is obtained that indicates the total daily energy requirement.

Application of BMR

BMR is a very important indicator in dietetics, as it allows you to find a starting point for implementing nutritional intervention. Based on the estimated BMR and level of physical activity, you can determine how many calories in your diet are needed to lose or gain weight. Even if these calculations are not accurate, by observing changes in body weight over a period of 2-3 weeks, it is easy to see whether the amount of calories was adequate for your needs, or whether it exceeded or fell short of them. In this case, it is worth making moderate adjustments in one direction or the other.