Why doctors still use BMI
BMI needs only a tape measure and a scale, costs nothing and gives comparable numbers across clinics and countries. Large studies link a BMI well above or below the healthy range with higher rates of type 2 diabetes, heart disease, some cancers and early death. As a first screening step it works well; the next steps — waist measurement, blood tests and a conversation about lifestyle — add the detail BMI cannot give.
BMI after 65
In older adults, being underweight is linked with frailty, falls and slower recovery from illness, and several large studies have found the lowest risk at a BMI somewhat above 25. Many clinicians therefore accept a BMI of about 23–30 after 65. Unplanned weight loss at this age is always worth discussing with a doctor.
Healthy weight in kilograms by height
The weight in kg at the bottom (BMI 18.5) and top (BMI 24.9) of the healthy range, and where obesity begins (BMI 30):
| Height | BMI 18.5 | BMI 24.9 | BMI 30 |
|---|---|---|---|
| 150 cm | 41.6 kg | 56.0 kg | 67.5 kg |
| 155 cm | 44.4 kg | 59.8 kg | 72.1 kg |
| 160 cm | 47.4 kg | 63.7 kg | 76.8 kg |
| 165 cm | 50.4 kg | 67.8 kg | 81.7 kg |
| 170 cm | 53.5 kg | 72.0 kg | 86.7 kg |
| 175 cm | 56.7 kg | 76.3 kg | 91.9 kg |
| 180 cm | 59.9 kg | 80.7 kg | 97.2 kg |
| 185 cm | 63.3 kg | 85.2 kg | 102.7 kg |
| 190 cm | 66.8 kg | 89.9 kg | 108.3 kg |
| 195 cm | 70.3 kg | 94.7 kg | 114.1 kg |