Understanding BMI categories
- Underweight: below 18.5
- Normal weight: 18.5 – 24.9
- Overweight: 25.0 – 29.9
- Obesity: 30.0 and above
What BMI is — and what it isn't
BMI (body mass index) is a simple screening tool that compares your weight to your height. It is quick, free, and useful at a population level, but it does not directly measure body fat, and it has real limitations:
- Very muscular people can have a high BMI with little body fat.
- Older adults often carry less muscle, so BMI can underestimate body fat.
- It does not account for where fat is stored (belly fat vs. elsewhere).
Other useful measures
Waist circumference and waist-to-hip ratio are often used alongside BMI. A large waist can signal higher risk even at a "normal" BMI. Use BMI as one data point, not a diagnosis, and talk to a professional for personalized guidance.