Editing Body mass index (section)

===Scaling===
The BMI depends upon weight and the ''square'' of height. Since mass increases to the ''third power'' of linear dimensions, taller individuals with exactly the same body shape and relative composition have a larger BMI.<ref>{{cite journal | vauthors = Taylor RS | title = Letter to the editor | journal = Paediatrics & Child Health | volume = 15 | issue = 5 | pages = 258 | date = May 2010 | pmid = 21532785 | pmc = 2912631 | doi=10.1093/pch/15.5.258}}</ref> BMI is proportional to the mass and inversely proportional to the square of the height. So, if all body dimensions double, and mass scales naturally with the cube of the height, then BMI doubles instead of remaining the same. This results in taller people having a reported BMI that is uncharacteristically high, compared to their actual body fat levels. In comparison, the [[Ponderal index]] is based on the natural scaling of mass with the third power of the height.<ref>{{cite web | vauthors = Bonderud D | title = What is the Ponderal Index? | work = The Health Board | date = 9 September 2023 | url = https://www.infobloom.com/what-is-the-ponderal-index.htm}}</ref>

However, many taller people are not just "scaled up" short people but tend to have narrower frames in proportion to their height.<ref>{{cite journal | vauthors = Sperrin M, Marshall AD, Higgins V, Renehan AG, Buchan IE | title = Body mass index relates weight to height differently in women and older adults: serial cross-sectional surveys in England (1992-2011) | journal = Journal of Public Health | volume = 38 | issue = 3 | pages = 607–613 | date = September 2016 | pmid = 26036702 | pmc = 5072155 | doi = 10.1093/pubmed/fdv067 }}</ref> [[Carl Lavie]] has written that "The B.M.I. tables are excellent for identifying obesity and body fat in large populations, but they are far less reliable for determining fatness in individuals."<ref>{{cite web | vauthors = Brody JE | date = 31 August 2010 |url=https://www.nytimes.com/2010/08/31/health/31brod.html|title=Weight Index Doesn't Tell the Whole Truth|work=[[The New York Times]] |url-status=live| archive-url=https://web.archive.org/web/20170501153306/http://www.nytimes.com/2010/08/31/health/31brod.html |archive-date=1 May 2017}}</ref>

For US adults, exponent estimates range from 1.92 to 1.96 for males and from 1.45 to 1.95 for females.<ref>{{cite journal | title = Weight-height relationships and body mass index: some observations from the Diverse Populations Collaboration | journal = American Journal of Physical Anthropology | volume = 128 | issue = 1 | pages = 220–229 | date = September 2005 | pmid = 15761809 | doi = 10.1002/ajpa.20107 | author1 = Diverse Populations Collaborative Group }}</ref><ref>{{cite journal | vauthors = Levitt DG, Heymsfield SB, Pierson RN, Shapses SA, Kral JG | title = Physiological models of body composition and human obesity | journal = Nutrition & Metabolism | volume = 4 | pages = 19 | date = September 2007 | pmid = 17883858 | pmc = 2082278 | doi = 10.1186/1743-7075-4-19 | doi-access = free }}</ref>