Another question on a similar theme: 

Please provide recommendations for standardisation for anthropometry fro adolescents - what is the agreed best measurement for adolescents? UK growth charts now in BMI-for-age z-scores but noted that the specialist nutrition units still work with % wt/ht targets. Many using adult BMI cut offs which do not fit wiht adolescent growth patterns.

Globally, the most appropriate and common option for now is BMI-for-age z-score based on either the WHO 2007 or IOTF references. We really don't want to be applying adult BMI cut-off to adolescents. The BMI-for-age z-scores are still not ideal - individual growth spurts are not taken into consideration and reference populations are also not hugely globally representative. But these are the best we have for now. Ideally we would like all the UN agencies to agree one gold standard measurement for adolescent thinness and overweight, and recommend it is measured in combination with diet adequacy data.