Your metabolic age combines three signals: BMR (calculated from the Schofield equation, NHMRC standard), waist-to-height ratio (a strong WHO marker of metabolic health), and your activity level. If your BMR is lower than expected for a healthy weight at your age, or your waist:height ratio is elevated, your metabolic age rises above your chronological age. The opposite shifts it younger. It’s an estimate, not a diagnosis — but it’s a meaningful signal of where your metabolism actually sits.

Waist-to-height ratio is one of the strongest predictors of metabolic disease risk in clinical research — often stronger than BMI. A WHtR above 0.5 typically signals increased visceral fat (the metabolically active fat stored around organs), which directly affects insulin sensitivity, inflammation and hormonal balance. After 35, this matters far more than your weight on the scale. Including waist gives a much more honest picture than age, weight and height alone.

Yes — and faster than most women expect. Metabolic age is not fixed. After coaching women since 2017, what I see consistently is that the body responds well when given the right inputs in the right order. Strength training to build muscle (protects BMR), adequate protein (1.4–1.6g per kg), stable blood sugar, addressing sleep and cortisol, and reducing visceral fat through diet quality — not chronic restriction. A 12-week structured approach can shift metabolic age by 5–15 years in many cases.