Health
A study tracking over 120,000 people for 16 years has revealed that the BMI, the standard tool physicians use to assess obesity, gives a misleading picture as people grow older.
Health
They compared BMI against three measurements of waist size: waist circumference, waist-to-hip ratio, and waist-to-height ratio.
Health
Obesity, measured by waist circumference, increases steadily with age until people reach their seventies or eighties.
Health
BMI, however, follows a different path. It climbs through adolescence and middle age, peaks around 50, then descends in older adults.
Health
Unlike BMI and other waist measures, it uses a single threshold regardless of age or sex. A person simply divides their waist circumference by their height. If the ratio exceeds 0.5, they face an elevated risk.
Health
The findings also support recent updates to UK obesity guidelines, which now recommend using the waist-to-height ratio alongside BMI rather than relying on BMI alone.