This interesting article proved that these body mass index drawings, "figures" in the picture below1, are actually useful. People can describe themselves accurately by choosing a picture. Go ahead, try it yourself. From that, they can basically know their approximate BMI. Cool.
Men’s average BMI for each figure-number was shown in this table
| Men: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
|---|---|---|---|---|---|---|---|---|---|
| BMI: | 19.8 | 21.1 | 22.2 | 23.6 | 25.8 | 28.1 | 31.5 | 35.2 | 41.5 |
Women’s average BMI for each figure-number was:
| Women: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
|---|---|---|---|---|---|---|---|---|---|
| BMI: | 18.3 | 19.3 | 20.9 | 23.1 | 26.2 | 29.9 | 34.3 | 38.6 | 45.4 |
Did you try it? Does your actual BMI seem close to the averages from these tables?
Well, maybe not. It turns out that BMI changes with age, even if your body shape (figure-number) stays the same during your life. More on this below.
This article also showed that when obesity is defined as BMI of 30 or more, the graphs below showed that obese women had figure=6, and obese Men had figure=7 (or higher).
The article also did additional analyses and claims that figure=6 is the best overall definition of "obesity" for both men and women. However, their article lacked sufficient detail to prove this claim, and although it may be reasonable for women, my personal opinion, based on the graphs shown above, is that figure 7 is a more suitable definition of obesity for men.
Now, here an the interesting part: BMI changes with age. Consider slim women and men, with figure numbers 3 and 4. As the graph below shows, Men and Women who described their body figures as type 3 or 4, also had higher BMI values in middle ages, compared to younger or older adults. Said another way, it seems that, even if body shape stays stable with age, BMI will change with age.
I was looking for evidence like this, and I think it is an important demonstration of what the appropriate curve-shape should be, of body mass index changing with age.
References
- Standard figural stimuli. by Dr. A. Stunkard. From Stunkard A, Sorensen T, Schulsinger F. Use of the Danish Adoption Register for the study of obesity and thinness. In: Key S, Roland I, Sigman R, Matthysse S (eds). The genetics of neurological and psychiatric disorders. Raven Press: New York; 1983.
