Title of article:
Body Mass Index Guidelines: Corresponding %Fat Standards Based on Three-Country Study
Authors: Gallagher D, Heymsfield SB, Heo M, Jebb S, Murgatroyd
P, Sakamoto Y.
Presented at: 9th European Congress on Obesity June 1999.
Abstract
Objective: International agencies have now adopted BMI standards for underweight (i.e.,<18.5), overweight (25), and obesity (30). There are no accepted %fat levels corresponding to these ranges despite increasing interest in quantifying body fat.
Design: Body fat was measured in US, UK, and Japan using state-of-the art methods (4-compartment [C] method [measured 3H2O dilution vol; body density; bone mineral] in 2 countries and DXA in all 3) and %fat prediction equations were developed based on BMI and other independent variables. Subjects were multiethnic healthy adults (n for US, UK, and Japan, 924, 205, and 924) with BMI35 ranging in age from 18-94 years.
Results: Strong correlations existed between 4-C and DXA %fat for US and UK centers (R2=0.85-0.94, p's<0.001). DXA %fat prediction models at all 3 centers were similar and included BMI and age as independent variables (R2=0.50-0.81, p's <0.001). There were small between-center differences in predicted %fat (max 3%) that varied with age and gender. The mean predicted %fat for 3 countries is shown in the table. This approach and initial findings provide the groundwork for establishing international standards for healthy body fat ranges.
Comments and Key points
This abstract was presented at a scientific meeting, and reproduced on the Tanita Corporation website1. I also reproduce it here because the presentation contained the interesting data in the table below, showing the Body Fat Percentages that occur at a BMI of 25 kg/m2.
| Women | Age | ||
|---|---|---|---|
| BMI | 20-39 yrs | 40-59 yrs | 60-79 yrs |
| 18.5 | 20.5% | 21.3% | 22.1% |
| 25.0 | 35.0% | 35.8% | 36.6% |
| 30.0 | 41.9% | 42.7% | 32.5% |
| Men | Age | ||
|
BMI |
20-39 yrs | 40-59 yrs | 60-79 yrs |
| 18.5 | 8.5% | 10.2% | 11.9% |
| 25.0 | 21.2% | 22.9% | 24.5% |
| 30.0 | 27.2% | 28.9% | 30.5% |
It is generally accepted than Men's "Overweight" threshold occurs at 25% body fat (and above). So notice that when BMI = 25 in the table, the body fat % values are significantly lower than 25%. This is evidence that a BMI overweight threshold for men, should be higher than 25 kg/m2.
Women's "Overweight" threshold is less well established, but 33% body fat is commonly used. So, notice that when BMI = 25 in the table, women's body fat % values are already higher than 33%. This is evidence that a BMI overweight threshold for women, should be lower than 25 kg/m2.
References
- http://www.tanita.com/professional/abstracts/abstract_7.html
Review & comments by Steven B. Halls, MD, November 10, 2003 Copyright.
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