Obesity in the NFL

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Hi All,

The below revisits the issue of obesity in the NFL.

Obesity in the NFL

Gerson T. Lesser

JAMA. 2005;293:2999.

To the Editor: In their study of obesity in the National Football League (NFL),1

Dr

Harp and Ms Hecht address the relatively high weights of professional football

players by considering the body mass index (BMI), calculated as weight in

kilograms

divided by the square of height in meters. Throughout this study, the authors

use

high BMI as a synonym for obesity. However, although BMI has been widely used

for

several decades, it does not separate or define the several components of body

composition, and its interpretation fails to deal with the rather broad range of

interindividual variability of lean body mass (LBM) at each given height.

Obesity

can be defined validly only as some excess proportion of body fat. Even in

small,

healthy populations of similar age and sex, normal LBM varies by plus or minus

20%

about the mean for height and age.2 Professional football players are probably

several standard deviations higher than the mean LBM of random young US male

populations, and as athletes in training, one might assume their actual

proportion

of body fat to be relatively low.

The authors state their belief that it is unlikely that the high BMI in this

group,

particularly in the class 2 obesity range, is due to a healthful increase in

muscle

mass alone. However, during World War II, many professional football players

were

deemed overweight by military service criteria. The rejection of obviously

healthy

and well-conditioned young men prompted a naval medical officer, Albert Behnke,

to

study methods to define body fat mass and LBM. Using densitometry, he showed

that

overweight football players rejected for military service actually had smaller

proportions of body fat than a group of nonathletic young naval men.3 These

pioneering studies helped initiate the modern study of body composition.

Despite much discussion, standards using height and weight information to

describe

body composition have defied clear resolution. When a standard such as BMI is

used,

its limitations must also be presented. In particular, equating the terms

" increased

BMI " and " obese " can be quite misleading, since excess body mass calculated

solely

from height and weight may be due only to excess fat, only to excess LBM, or to

any

combination of the two.2

1. Harp JB, Hecht L. Obesity in the National Football League. JAMA.

2005;293:1061-1062. FULL TEXT

2. Lesser GT, Deutsch S, Markofsky J. Use of independent measurement of body fat

to

evaluate overweight and underweight. Metabolism. 1971;20:792-804. ISI | MEDLINE

3. Welham WC, Behnke AR Jr. The specific gravity of healthy men: body

weight÷volume

and other physical characteristics of exceptional athletes and of naval

personnel.

JAMA. 1942;118:498-501.

Obesity in the NFL—Reply

Joyce B. Harp; Hecht

JAMA. 2005;293:2999.

In Reply: We agree with Dr Lesser that there are limitations in using BMI to

estimate body fatness in professional football players. We stated this in our

Research Letter, which we do not feel misled readers into believing that

increased

BMI, particularly at the lower range, equates with obesity. Lesser questions the

assertion that the extreme weights seen in some NFL players are not due to

increases

in lean body mass alone. We look forward to seeing definitive studies of body

composition and risk factor assessment in professional and amateur athletes with

high BMIs. Until then, we and others cannot assume that one’s status as a

professional athlete guarantees leanness and health.

Al Pater, PhD; email: old542000@...

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