Why WHtR matters
A 2010 meta-analysis (Browning et al., Nutrition Research Reviews) of 31 studies and over 300,000 adults found WHtR was a stronger predictor of cardio-metabolic risk than BMI or waist circumference alone. The relationship is largely mediated by visceral (abdominal) adiposity, which drives insulin resistance, lipid abnormalities and elevated blood pressure.
The “keep your waist under half your height” rule
Below 0.50 — for both sexes, all adult ages — is the simple takeaway. NICE consolidated this into formal 2022 guidance because the rule is easy to measure, language-independent, and works whether you’re using cm or inches.
What this number doesn’t tell you
WHtR is a screening signal, not a diagnosis. Two people with identical 0.55 ratios can have very different metabolic profiles depending on activity level, lipid panel, blood-pressure history, and family genetics. Use this number as one input to a conversation with your Canadian healthcare provider, not as a self-administered diagnosis.