BMI is the indicator most often used to assess excess weight, but the distribution of excess fat in the body is also relevant. For example, excessive fat in the trunk or abdomen (central obesity) is associated with greater risk of type 2 diabetes, hypertension and heart disease, compared to excess fat on the hips or legs. Increased risk of colorectal cancer is associated with BMI in men but with waist-to-hip ratio in women.10,11

NHS guidance advises that men with a waist size of ≥94cm (37 inches) and women with a waist size of ≥80cm (31.5 inches) are more likely to develop obesity-related health problems.12

A practical approach for most people advising on weight loss and the health risks of being overweight is to consider BMI and waist measurements together.

NICE guidance on the appropriate level of intervention depending on BMI and waist measurement has been published.13