Obesity and metabolic syndrome
Description
- A chronic, relapsing, progressive disease of energy regulation - not a failure of willpower
- The set-point is defended: weight loss triggers dec leptin, inc ghrelin and dec resting energy expenditure that persist for years
Classification
| BMI (kg/m2) | Class |
|---|---|
| 25-29.9 | Overweight |
| 30-34.9 | Obesity class I |
| 35-39.9 | Class II |
| >=40 | Class III |
- *Asian populations: thresholds shift down - overweight >=23, obesity >=25 (greater visceral fat and metabolic risk at any BMI*)
- BMI is a screening tool, not a diagnosis - add waist circumference (M >=94 cm, F >=80 cm; lower in Asian populations) or waist:height ratio >0.5
- *2025 Lancet Commission split*
- Clinical obesity - excess adiposity with organ dysfunction or limitation of daily activity -> a disease in its own right
- Pre-clinical obesity - excess adiposity, preserved function -> a risk state
- Intended to stop both under-treating the sick and over-medicalising the well
Metabolic syndrome (IDF/harmonised) - any 3 of 5
- Waist circumference above population/ethnicity-specific cutoff
- Triglycerides >=1.7 mmol/L (or treated)
- HDL <1.0 (M) / <1.3 (F) mmol/L (or treated)
- BP >=130/85 (or treated)
- Fasting glucose >=5.6 mmol/L (or T2DM)
- Its value is as a prompt, not a diagnosis - it adds little to calculated absolute cardiovascular risk
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