Relying on your BMI as an accurate gauge of a healthy weight has been superseded by a more accurate measure. Find out what it is and if you need to worry.
A BMI under 25
A waist-to-hip ratio under 0.9
In a University of Texas study, up to 10 per cent of men with physically active jobs were wrongly classified as obese using BMI criteria. BMI estimates fail to distinguish between muscle and fat; in fact, after assessing more than 15,000 adults, Mayo Clinic researchers found that men with high waist-to-hip ratios were twice as likely to die over the 14-year study period as men with high BMIs.
To calculate your ratio, measure your waist at your belly button and your hips at their widest point. Divide the first number by the second; 0.9 or above means you have too much visceral fat, the kind that promotes type 2 diabetes and high blood pressure.
To flatten your belly, crank up the intensity. In a University of NSW study, men who did 20-minute interval sessions three times a week on an exercise bike – alternating between eight-second sprints and 12-second rests – reduced their belly size (and visceral fat) more than those cycling at a moderate pace.
Related: Torch 1000 Calories – Fast