What is BMI (Body Mass Index)?
Body Mass Index (BMI) is a simple, internationally recognized health metric that uses your weight and height to estimate total body fat. It is typically used as a screening tool by healthcare providers to identify potential weight categories that may lead to health problems.
How is BMI Calculated?
The BMI formula is universally standard, though it differs slightly based on the measurement system you use:
- Metric System: BMI = Weight (kg) / [Height (m)]²
- Imperial System: BMI = Weight (lbs) / [Height (in)]² × 703
Standard BMI Categories
According to the World Health Organization (WHO), adult BMI is divided into the following categories:
- Underweight: Less than 18.5
- Normal weight: 18.5 – 24.9
- Overweight: 25.0 – 29.9
- Obesity: 30.0 or greater
Limitations of BMI
While BMI is a useful general guideline, it is not a diagnostic tool and has several well-documented limitations. Because BMI only uses weight and height, it does not distinguish between muscle mass, bone density, and body fat. For instance, athletes and bodybuilders with high muscle mass may have a "high" BMI while having very low body fat percentages. Older adults who have lost muscle mass may fall into a "normal" BMI range despite having excess body fat. Always consult a healthcare professional for a comprehensive health assessment.