BMI or body mass index

BMI (Body Mass Index) - Indice de Quetelet is a method invented by the Belgian statistician Adolf Kittel (1796-1874) to calculate the degree of obesity in the human body. Body mass index indicates whether a person's body weight is healthy in relation to a person's height (height).

To calculate the body mass index, you need to divide the weight (in kilograms) by the square of the height (in meters).

The World Health Organization (WHO) recommends a healthy BMI range of 18.5 to 25 for both men and women. It is widely used in medicine as a rapid indicator of potential health complications. In general, the higher your body weight, the more likely you are to suffer from health problems such as obesity, diabetes, heart disease and more. Doctors use BMI to inform their patients about possible health problems, especially if there is a gradual increase in their BMI, and this is currently the official indicator for classifying people according to their level of obesity.

BMI ranges vary by factors such as region and age, and are sometimes subdivided into categories such as very low weight or very obese. Being overweight or underweight can have a significant impact on health, so although BMI is not a completely accurate method of calculating healthy body weight (because the relationship between muscle and fat mass is not taken into account),

it is widely used in the initial diagnosis of healthy weight because it is fast and accurate enough for 90-95% people.

What to consider when interpreting the calculated BMI

Although BMI (body mass index) is a widely used and useful indicator of healthy body weight, it has its limitations. It is important to remember that BMI is only a calculation that does not take into account body composition. Because body types, muscle, bone mass, and fat distributions vary from person to person, BMI should be used in conjunction with other measurements and not as the sole method of determining a person's healthy body weight.

BMI differences in adults

BMI cannot be completely accurate as it is a measure of body weight, not an indicator of excess body fat. BMI is also affected by factors such as age, gender, ethnicity, muscle and body fat mass, and level of physical activity. For example, an older person may have a BMI in the healthy weight range, but if they are completely inactive in their daily lives, they may have significant amounts of body fat.

In contrast, a BMI in a young person with high muscle mass may indicate an unhealthy weight.

For athletes and people who are physically active (muscle mass is higher than the average individual), the calculated BMI may be in the overweight range because muscle is heavier than fat.

In most cases:

• Older adults tend to have more body fat than younger people with the same BMI.
• Women usually have more body fat than men with equivalent BMI.
• Muscled individuals and trained athletes may have higher BMI due to higher muscle mass.

BMI differences in children and adolescents

Children and adolescents are subject to the same BMI constraints as adults. In addition, children's height and level of sexual maturation can affect BMI and body fat. BMI as an indicator of excess body fat is better in obese children than in overweight children, whose BMI could be affected by increased levels of fat or non-fat mass (all parts of the body except fat, which includes water, organs, muscles, etc.). In thin children, the difference in BMI may also be related to lean mass.

Classification of BMI results in children (2-20 years)

The weight calculator is designed to determine increasing BMI. For children (under 20 years of age - the body is growing), the calculation of the body mass index is identical, but a more detailed classification scale is used (gender and age are taken into account, BMI is also calculated by months. children in percentiles.).

Body mass index age precentiles for boys aged 2 to 20 years

Body mass index age precentiles for 2 to 20 year old girls

Basic metabolism

dietsabc.com calculator is used to calculate basal metabolic rate (BMR) Harris-Benedict equation.

The Harris-Benedict equation was one of the first to be used to calculate the basal metabolic rate (BMR), the amount of energy that the human body consumes at rest in a single day. The formula was refined in 1984 and was used as the only practical calculation method until 1990, when the Mifflin-St Jeor equation appeared.

The Katch-McArdle formula differs slightly in that it calculates energy consumption at rest rather than at rest and takes into account lean body mass, which does not take into account either the Miflin-Stjeor or Harris-Benedict equation. Of these equations, the Mifflin-St Jeor equation is considered the most accurate for calculating BMR, while the Katch-McArdle formula may be more accurate for people who are thinner and know their body fat percentage.

Mifflin-St Jeor equation

For men: BMR = 10 W + 6.25 H - 5A + 5

For women: BMR = 10 W + 6.25 H - 5A - 161

The revised Harris-Benedict equation

For men: BMR = 13.397 W + 4.799 H - 5.677 A + 88.362

For women: BMR = 9.247 W + 3.098 H - 4.330 A + 447.593

Katch-McArdle equation

BMR = 370 + 21.6 (1 - F) W

Abbreviations:

W is the body weight in kg

H is the length of the body in cm

A is age

F is the percentage of body fat

Ideal weight

Several formulas have been developed to determine the ideal weight and depending on which one is used in the calculations - the ideal weight for the same person can vary up to 10 kg. The dietsabc.com calculator uses a formula published by GJ Hamwi in 1964, which was originally used to determine the dose of medication a person needs.

What is your ideal weight?

Most of us have ever tried to lose weight, some have succeeded, some have not. The ideal weight can be determined in different ways - for some it is the weight at which their physical well-being is best, for others - the weight at which they feel best emotionally.

Today, the notion of an ideal body weight is based on the visual appeal created by the media, that is, the ideal of beauty is a variable, for example, a few hundred years ago it was a round pale aristocracy compared to the heels and tanned peasants.

The concept of Ideal body weight (IBW) was introduced to determine the dose of medication a person needs and the formulas that calculate it were not related to how the person looks or feels physically and emotionally at that weight (medication doses are based on IBW , rather than total body weight). Today, IBW is also widely used outside of medicine, for example in sports in which athletes are classified according to their body weight (weight category).

Note that IBW is not an ideal measurement because it does not take into account the percentage distribution of body fat and muscle in the human body. This means that the ideal body weight for athletes and physically active people is higher than calculated. Remember that the calculated ideal weight does not always indicate health or the weight that a person should definitely aim for - it is possible that your IBW may be above or below the calculated one and you are also completely healthy.

How exactly one should weigh for each individual is not precisely determined. It largely depends on each individual. So far, there is no measure, neither IBW - ideal body weight, nor BMI - body mass index or anything else that can determine exactly how much a person should weigh in order to be healthy. All of these methods are good for initial diagnosis, but if they indicate an unhealthy body weight, consult your doctor first before considering which diet to choose.

To maintain your health it is more important to follow a healthy lifestyle and basic principles of healthy nutritionthan to strive for a certain weight on the basis of a generalized formula. Maintaining a healthy weight can be helped, for example, by regular physical activity, the use of fresh rather than industrially processed products in your diet, enough sleep, and so on.

The main factors influencing the ideal weight

Age

Theoretically, age should not significantly affect IBW in girls after 14-15 years of age and in boys after 16-17 years of age, when most people stop growing. It is important to remember that the height of men and women decreases by 3.8 - 5 cm until the age of 70, and as people age, muscle mass decreases and excess body fat accumulates more easily. It is a natural process, but it can be slowed down, for example, by a healthy diet, physical activity and enough sleep.

Gender

Women generally weigh less than men, although they naturally have a higher percentage of body fat. This is because the male body usually has more muscle mass and the muscles are heavier than fat. Women also tend to have lower bone density and are smaller in stature than men.

Length

The taller a person is, the greater their muscle and body fat mass, resulting in weight gain. If a man and a woman are the same height (in length) - a man should be about 10-20% heavier.

Body type

Body type (skeletal bone size) is another factor that can affect the determination of ideal weight (within a few kg). It is usually classified as small, medium or large (fine bones, medium wide bones, wide bones). It is measured on the basis of the circumference of the human wrist in relation to height. You can see how to properly measure the circumference of your wrist HERE. The classification is as follows:

For women less than 158.5 cm tall

• Fine bones = wrist size less than 12.7 cm.
• Medium wide bones = wrist size from 12.7 cm to 14.6 cm.
• Broad bones = wrist size greater than 14.6 cm.

For women whose height ranges from 158.5 to 167.6 cm

• Fine bones = wrist size less than 15.2 cm.
• Medium wide bones = wrist size from 15.2 cm to 15.9 cm.
• Broad bones = wrist size over 15.9 cm.

For women over 167.6 cm tall

• Fine bones = wrist size less than 15.9 cm.
• Medium wide bones = wrist size from 15.9 cm to 16.51 cm.
• Broad bones = wrist size greater than 16.51 cm.

For men whose height is over 167.6 cm

• Fine bones = wrist size from 14 cm to 16.5 cm.
• Medium wide bones = wrist size from 16.5 cm to 17.8 cm.
• Broad bones = wrist size over 17.8 cm.

A person with wide bones, of course, weighs more than a person with fine bones of the same height - this applies to both IBW and BMI calculations.

The most popular formulas for determining the ideal weight

The formulas differ in the values used, based on the research and findings of the scientists involved in their development. The Devine formula is the most widely used formula for measuring IBW.

J. Hamwi formula (1964)

It was developed for drug dosing purposes.

Men: 48.0 kg + 2.7 kg per inch over 5 feet

For women: 45.5 kg + 2.2 kg per inch over 5 feet

J. Devina formula (1974)

Like Hamwi's formula, it was originally designed to calculate the dose of a medicine based on your weight and height. Over time, the formula became a universal method for calculating IBW.

For men: 50.0 kg + 2.3 kg per inch over 5 feet

For women: 45.5 kg + 2.3 kg per inch over 5 feet

J.D. Robinson formula (1983)

Modification of the Devine formula.

Men: 52 kg + 1.9 kg per inch over 5 feet

For women: 49 kg + 1.7 kg per inch over 5 feet

R. Millera formula (1983)

Modification of the Devine formula.

Men: 56.2 kg + 1.41 kg per inch over 5 feet

For women: 53.1 kg + 1.36 kg per inch over 5 feet

Calorie calculator

Calorie counting is a generally accepted and very effective method of weight control. Each food package states exactly how many calories there are in 100g of a particular product - this makes counting calories relatively easy.

How many calories do you need

Usually people start to be interested in energy consumption and calorie counting in order to lose weight, because the easiest way to lose weight is to consume fewer calories every day.

But how many calories does the body need to be healthy and able to function normally? It largely depends on age, weight, height, gender and level of physical activity - so it is different for each person.

For example, a physically active 180-year-old 180 cm tall man needs significantly more calories than a 160 cm tall 70-year-old woman with a sedentary lifestyle. Adult men usually need 2,000 to 3,000 calories a day to maintain their weight, while adult women need about 1,600 to 2,400 calories a day.

The body does not need many calories to just survive. However, by consuming too few calories, the body functions poorly because energy (calories) is used only for vital functions. Several studies show that women need to consume at least 1,200 calories a day and men at least 1,500 calories a day.

It is usually difficult for a layman to determine how many calories he needs in a matter of days to maintain his weight, to lose weight without gaining health, or to gain weight.

The dietsabc.com Calorie Calculator calculates the amount of calories you need by first calculating your Basic Metabolism multiplied by your physical activity rate (1.2-1.95).

The amount of calories needed for gradual weight loss is calculated by applying a 15% calorie deficit, and for rapid weight loss - a 30% calorie deficit. It is not recommended to reduce your calorie intake by more than 30% per day because Too much weight loss is bad for your health and slowing down your metabolism in the near future can have the opposite effect of losing weight.

It is important to remember that a proper and balanced diet for weight loss is especially important, because if the body is deprived of the necessary nutrients, both health and beauty problems (skin, nail, hair health) can begin.

Sources:

Official website of the US Centers for Disease Control and Prevention.

https://www.ncbi.nlm.nih.gov/

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