Question to the Department of Health and Social Care:

To ask His Majesty's Government what recent assessment they have made of the accuracy of BMI thresholds for (1) adults, and (2) children.

The National Institute for Health and Care Excellence (NICE) recommends that Body Mass Index (BMI) for adults and BMI centile, adjusted for age and sex, for children and young people should be used as a practical measure for estimating and defining adiposity, the measure of fatty tissue. In September 2022, NICE reviewed evidence on the most accurate methods and thresholds for assessing the risk associated with overweight and obesity in adults, children and young people, which included BMI.

The Government accepts NICE’s evidence review and recommendations on BMI, including that: BMI is used as a practical measure of overweight and obesity in both adults and children and young people but needs to be interpreted with caution because it is not a direct measure of central adiposity, the accumulation of excess fat in the abdominal area which directly relates to health risks such as type 2 diabetes, hypertension and cardiovascular disease; in adults with a BMI below 35 kilograms per metre squared, waist-to-height ratio should be measured and used as well as BMI, as a practical estimate of central adiposity; in children or young people with a BMI on or above the 91st centile, waist to height ratio should be measured to estimate the degree of central adiposity to help identify or predict future health risks; and a child’s BMI centile should always be plotted on the Royal College of Paediatrics and Child Health UK-World Health Organization growth charts and BMI charts.

NICE also recommended further research, for adults as well as children and young people, on the most accurate and suitable measurements and boundary values to assess the health risks associated with overweight, obesity and central adiposity in people of different ethnicities, particularly those from black, Asian and minority ethnic family backgrounds.

The Department have noted NICE’s recommendations for research. The Department delivers research through the National Institute for Health and Care Research, which funds and supports research across all areas of health and social care, including obesity. Research proposals in all areas compete for the funding available, with awards made on the basis of scientific quality, value for money, and importance of the topic to patients and the health and care system.