Weight is a relative value. For one person, 60 kilograms can be the first stage of obesity, and for another - a sign of severe malnutrition. It is for this that, on the basis of a number of studies, specialists have derived a body mass index (BMI) or a weight and height coefficient. This coefficient allows you to independently determine at home how much your weight is normal without the help of a specialist.
Definition
Body mass index is a ratio of weight to height. It is used to determine whether a person has a healthy weight for his complexion or is at risk of underweight or overweight.
Deviation of the body mass index from normal significantly increases the risk of a wide variety of diseases, especially diseases of the joints and the cardiovascular system.
BMI values are the same for both sexes. Health risks associated with weight gain are continuous. However, depending on the population group, the weight and height coefficient is still interpreted with some changes.
Why is it important to maintain a healthy weight?
If you do not have diseases that lead to excess weight, then regular physical activity and proper nutrition will help you easily adhere to the norm. And this is necessary, first of all, not because of appearance, but because of a number of health benefits:
- lack of pain in muscles and joints;
- more energy and desire to participate in various events;
- improvement of blood circulation, stabilization of blood pressure;
- healthy, sound sleep;
- decrease in triglycerides and glucose in the blood;
- reducing the risk of heart disease and several types of cancer.
Being overweight places a heavy strain on the heart, raises blood pressure, and cholesterol levels.
What are the effects of obesity?
Obese people are at risk. Being overweight can cause the following diseases and conditions:
- High mortality rate.
- Hypertension.
- Elevated levels of low density lipoproteins (“bad” cholesterol) and lower levels of high density lipoproteins (“good” cholesterol).
- Type 2 diabetes.
- Coronary heart disease.
- Strokes.
- Gallbladder disease.
- Osteoarthritis (destruction of cartilage in the joints).
- Sleep disturbances.
- Trouble breathing.
- Chronic inflammatory processes.
- Some types of cancer (breast, colon, kidney, gall bladder, and liver cancer).
- Low level of quality of life.
- Mental illnesses such as depression, anxiety, etc.
- Chronic pain and difficulty in moving.
Over the past few years, obesity has caused many suicides.
Is underweight dangerous?
The common misconception that being thin is good. As well as a high coefficient of weight and height, a lack of weight is a deviation from the norm and can lead to a number of serious diseases:
- infertility;
- amenorrhea in women;
- autoimmune diseases;
- type 1 diabetes;
- hyperthyroidism (thyroid disease);
- mental problems, depression, anxiety, anorexia nervosa;
- digestion problems.
In case of insufficient weight, it is also necessary to seek the help of specialists in order to identify the cause of the deviation and to develop the right diet and exercise system.
What is BMI used for?
A body mass index alone may not be a sufficient tool for a complete diagnosis. For example, the weight and height coefficient for men involved in weightlifting very often does not correspond to the statistical norm. This is due to the fact that the values are determined for an "ordinary" person, with a small amount of muscle. In the case of people with significant muscle mass, the results may be erroneous.
That is why, to identify potential problems with weight, a specialist also needs to perform the following actions:
- measure the thickness of the skin fold to determine the percentage of fat mass;
- analyze diet and physical activity;
- find out about weight problems among the next of kin;
- make additional analyzes as necessary.
A high body mass index does not always indicate obesity, but in order to determine whether such a weight is hazardous to health, it is important to consult a specialist.
How to calculate the weight and height ratio on your own?
A Belgian scientist, one of the founders of statistics, Adolf Quetelet developed a formula for determining BMI about 150 years ago.
Of course, over 150 years there have been many changes. Not only the complexion of a person has changed, but also the way of life. This effect did not affect the formula itself, however, modern scientists have corrected the data by which today it is possible to determine the coefficient of weight and height.
The formula for calculating body mass index is quite simple: it is necessary to divide the weight in kilograms by the height (in meters) squared.
For example, a girl who is 160 cm tall and weighs 55 kg. BMI for her will look like this 55 / 1.6 2 = 21.5
It is enough to compare the obtained value with the table below, and now you already know whether your weight is within the normal range.
The weight and height coefficient for women and men is the same and equal to:
Less than 18.5 | Underweight |
18.5 - 24.9 | Healthy, normal weight |
25.0 - 29.9 | Overweight |
Over 30 | Obesity |
If you go back to the example, then, according to the table, the body mass index of our girl is within normal limits. There are no health hazards directly related to weight.
How well does BMI characterize the percentage of body fat?
The relationship between BMI and body fat is quite strong. However, even in people whose weight and height ratio is as similar as possible (up to hundredths of a thousandth), the percentage of fat mass can vary significantly.
With the same body mass index:
- in women, as a rule, the percentage of body fat is higher than in men;
- depending on race, whites have more fat than blacks and less than Asians;
- athletes have less body fat than people with minimal physical activity.
A high ratio of weight and height does not always indicate excessive obesity. A BMI higher than normal can equally indicate a high level in the body of both fat and muscle mass.