Body mass index


The article discusses:

  • Classic body mass index
  • Indicators of dependence of body mass index with dietary problems
  • Possible errors in body mass index measurements
  • Additional health risk factors (high cholesterol) predicted by body mass index values
  • Health risk factors not related to body mass index
  • Preliminary assessment of the need to lose weight by body mass index

Classic body mass index

Body mass index – the most common indicator of the ratio of height and weight of a person. For the first time, this indicator was proposed in the middle of the 19th century by Adolphe Quetelet (Belgium) to substantiate a classification of body types independent of a person’s race. Now for this indicator a close relationship has been established with a number of diseases dangerous to health (including cancer, strokes, heart attacks, high cholesterol or other disorders of lipid metabolism, etc.).

Scheme for calculating the classic body mass index: a person’s weight in kilograms is divided by the square of his height in meters – this scheme does not provide an accurate estimate for athletes and the elderly. Unit of measurement – kg / m2.

Based on the rounded value, it is concluded that there are nutritional problems.

Indicators of dependence of body mass index with dietary problems

Currently, it is generally accepted that the following division of nutritional problems is based on the calculated values ​​of the body mass index. The classic body mass index is taken into account.

BMI value Nutritional Problems
to 15Severe mass deficit (possible anorexia)
from 15 to 18,5Body weight is insufficient
from 18,5 to 25 (27)Normal body weight
from 25 (27) to 30Body weight above normal
from 30 to 35First degree obesity
from 35 to 40Second degree obesity
more 40Obesity of the third degree

The values ​​in parentheses are different from those currently generally accepted and are based on the latest nutritional research. Conventional view: outside BMI values ​​18,5 – 25 kg / mXNUMX2 the relative number of dangerous diseases increases sharply in comparison with neighboring values. But an increase in body mass index to values ​​of 25 – 27 kg / m2 leads to an increase in life expectancy, compared with people whose weight is normal (according to the calculation scheme classic body mass index). In other words, the upper limit of normal body mass index (for men) is increased by 8 percent relative to the generally accepted.

Possible errors in body mass index measurements

Although body mass index is a reliable indicator of a predisposition to a number of diseases (a clear sign of a disease in dietetics), this indicator does not always give correct results.

There are at least two groups of people for whom the body mass index does not always give correct results (additional assessment methods are needed to measure basal metabolism).

  • Professional Athletes – The ratio of muscle to adipose tissue is disrupted through targeted training.
  • Elderly people (the older the age, the greater the measurement error) – from 40 years of age, muscle mass decreases by an average of 5-7% every 10 years relative to its maximum at 25-30 years (accordingly, adipose tissue increases).

Additional health risk factors (high cholesterol) predicted by body mass index values

In addition to the presence of some degree of obesity, the following factors pose a threat to health (including for values ​​of 25-27 kg / m2 classic body mass index).

  • High blood pressure (hypertension).
  • Elevated LDL (Lipoprotein Low Density) cholesterol – the basis for blockage of arteries by atherosclerotic plaques – “bad cholesterol”.
  • Lower HDL cholesterol (Lipoprotein High Density – high density lipoprotein – “good cholesterol”).
  • Increases in triglycerides (neutral fats) – by themselves, are not associated with heart disease. But their high level forces high LDL cholesterol and lowering HDL cholesterol… And high triglyceride levels are a direct result of insufficient physical activity (or being overweight).
  • High blood sugar (causes an increase in triglycerides and, as a result, a decrease in HDL cholesterol and an increase in LDL cholesterol).
  • Low level of physical activity (the first and second professional groups in terms of physical activity) – causes a rapid increase in triglycerides, and then lower cholesterol HDL and increased LDL cholesterol.
  • High blood sugar (causes triglycerides to rise).
  • Smoking (in general, smoking causes a narrowing of the vascular cross-section, which aggravates the effects of high LDL cholesterol and lowering HDL cholesterol). It should be noted that within 5-10 minutes (depending on the type of cigarettes) after the smoked cigarette, the vessels expand, and further narrow more significantly, relative to the average level.

Health risk factors not related to body mass index

The factors below are not directly related to body mass index, but indirectly affect (for example, body type is genetically determined and practically cannot be adjusted).

  • There have been cases of heart disease in your family.
  • For women, the waist circumference is more than 89 cm.
  • For men, the waist circumference is more than 102 cm.

Preliminary assessment of the need to lose weight by body mass index

The need to lose weight is beyond doubt for people with a body mass index calculated in a diet selection calculator for weight loss:

  • greater than or equal to 30 kg / m2.
  • from the range of 27-30 kg / m2 in the presence of two or more risk factors (presented above), directly or indirectly associated with the body mass index.

Even a small weight loss (up to 10% of your current weight) will significantly reduce the risk of diseases associated with excess weight (a number of cancers, heart attacks, strokes, high LDL cholesterol, lipid metabolism disorders, diabetes, lowering HDL cholesterol, hypertension and many others).

Relative to the range of body mass index values ​​25-27 kg / m2 Without a more detailed assessment of your health, it is impossible to give a definite answer, even if you have two or more risk factors. Consultation with your doctor is required. It may be more beneficial for you to stay at your current weight (losing weight will hurt you), even if there is an increase in the values ​​when calculating the classic BMI (especially in light of recent research). It can only be stated unequivocally that it is desirable to prevent weight gain.

Leave a Reply