Body Mass Index

TLDR

BMI is a widely used anthropometric index for classifying adults and assessing health risk, but it poorly reflects body fat percentage, site‑specific fat distribution, and mortality risk varies modestly across a broad BMI range. This brief review aims to discuss the limitations of BMI as an indicator of body fat and health risk. The authors conduct a concise literature review to examine BMI’s shortcomings.

Abstract

The body mass index (BMI) is the metric currently in use for defining anthropometric height/weight characteristics in adults and for classifying (categorizing) them into groups. The common interpretation is that it represents an index of an individual's fatness. It also is widely used as a risk factor for the development of or the prevalence of several health issues. In addition, it is widely used in determining public health policies.The BMI has been useful in population-based studies by virtue of its wide acceptance in defining specific categories of body mass as a health issue. However, it is increasingly clear that BMI is a rather poor indicator of percent of body fat. Importantly, the BMI also does not capture information on the mass of fat in different body sites. The latter is related not only to untoward health issues but to social issues as well. Lastly, current evidence indicates there is a wide range of BMIs over which mortality risk is modest, and this is age related. All of these issues are discussed in this brief review.