Body Mass Index (BMI): What Your Number Means and How to Improve It
Body Mass Index (BMI): What Your Number Means
BMI is the first tool doctors use to gauge weight status โ one number from a simple division that says a lot, but not everything.
The Formula and Categories
BMI = weight (kg) รท [height (m)]ยฒ
| Range | Category |
|---|---|
| Under 18.5 | Underweight |
| 18.5 โ 24.9 | Normal โ |
| 25 โ 29.9 | Overweight |
| 30 โ 34.9 | Obesity class I |
| 35+ | Obesity class II+ |
What BMI Actually Tells You
WHO figures tie to real outcomes: heart disease, type-2 diabetes and hypertension risk clearly rises above 25, and jumps at 30.
But BMI Has Real Limits
It can't tell muscle from fat โ a 90kg, 180cm athlete may show "obese" at peak fitness. So:
- For athletes: measure body-fat % or waist
- Over 65: the healthy range shifts slightly up
- Children and pregnancy: entirely different tools
How to Lower It Sustainably
- Moderate deficit: 300โ500 kcal/day โ faster loses muscle, not fat
- Enough protein: 1.6โ2.2g per kg preserves muscle
- Weekly resistance training: 2โ3 sessions
- Sleep 7โ9 hours: short sleep measurably raises hunger hormones
- Patience: 0.5โ1% of body weight per week is the pace that sticks
Bottom Line
Use BMI as a starting point; re-check every 2โ4 weeks in identical conditions. The number is a trend, not a verdict โ consistency beats precision.