BMI (Body Mass Index) for obesity
The Body Mass Index has become a fundamental tool for assessing health and the risk of various conditions, especially obesity. We are going to explore in detail what BMI is, how it is calculated, its relevance in the identification and approach to obesity. You will discover how this metric has become a key indicator for health and well-being.
What is BMI and how is it calculated?
BMI is a measure that evaluates the relationship between a person’s weight and height, providing a general indication of the body fat level. The formula to calculate BMI is:
BMI= Weight (kg) / Height (m)²
Where weight is expressed in kilograms and height in meters. This calculation provides a number that is classified into specific categories, each associated with different weight ranges.
BMI Classification:
Underweight: BMI less than 18.5
Normal: BMI from 18.5 to 24.9
Overweight: BMI from 25 to 29.9
Obesity: BMI of 30 or higher
The Direct Relationship with Obesity:
BMI has been established as a reliable indicator for identifying obesity and assessing the risk of associated health problems. When BMI falls into the obesity category, the risk of cardiovascular diseases, type 2 diabetes, hypertension, and other weight-related conditions increases significantly.
Importance of BMI in Health Assessment
- BMI provides a quick and simple assessment of body composition, allowing early diagnosis of potential weight issues.
- An elevated BMI is directly associated with an increased risk of developing chronic diseases, highlighting its importance as a risk indicator.
- By knowing BMI, health professionals can establish personalized treatment guidelines to address obesity and improve overall health.
How good is BMI as an indicator of body mass?
The relationship between Body Mass Index (BMI) and the amount of body fat is strong, but even when two people share the same BMI, the proportion of body fat can vary significantly.
Typically:
- With the same BMI, women tend to have more body fat than men.
- With the same BMI, the amount of body fat may be higher or lower depending on the racial/ethnic group13-15.
- With the same BMI, older adults, on average, tend to have more body fat than younger adults.
- Those who practice sports, with the same BMI, usually have a lower proportion of body fat compared to non-athletes.
The accuracy of BMI as an indicator of body fat seems to be more reliable in individuals with elevated BMI and body fat levels¹⁶. Although it is likely that a person with a very high BMI (for example, 35 kg/m²) has a high proportion of body fat, a relatively high BMI may be due to a higher amount of body fat or a higher lean body mass (muscles and bones). It is crucial that a qualified health professional performs adequate assessments to evaluate the health and risks of each individual.
