How do you measure obesity using a waist-to-height ratio?

Changing how children are measured for obesity to a new system could be more accurate, a study has concluded.

It revealed the traditional method of using Body Mass Index (BMI) is not as useful in measuring fat as waist-to-height ratio (WHtR).

The Bristol project, part of the Children of the 90s study, was published in the journal Paediatric Research.

BBC West health correspondent Matthew Hill shows how to check your WHtR.