Despite the substantial limitations of the BMI standard, researchers continue to rely on it as their primary measure of obesity. In fact, essentially all obesity statistics have been calculated using the BMI. University of Alabama obesity researcher David Allison insists, "Analysts need to start retreating from relying solely on BMI." An article in QJM, the monthly journal of the Association of Physicians in Great Britain, warned in 2000:
"General applicability of BMI is challenged by results from studies of individual populations … Although BMI is a generally convenient measure, it lacks a theoretical foundation, and may be compromised by ethnic, cultural or lifestyle differences. Nonetheless, BMI has been used as a generic risk factor in epidemiological research of many pathological conditions, has been adopted as the main or sole measure of obesity in numerous clinical trials, and subsequently has been incorporated into clinical guidelines concerning screening for and treatment of various common diseases. Thus the weaknesses of the BMI could have important implications for public health specialists, for researchers and for clinical practitioners in many fields."Likewise, research published in 1998 in the International Journal of Obesity found:
"The results show that the relationship between percent body fat and BMI is different among different ethnic groups. This should have public health implications for the definition of BMI cut-off points for obesity, which would need to be population-specific… It is known that the relationship between BMI and body fat is age- and gender-dependent… A stocky person is likely to have more muscle mass/connective tissue than a slender person with the same body height. Thus, at the same BMI, the slender person will have more body fat… The consequences of the different relationships between body fat and BMI are evident. As increased body fat and not increased weight or BMI is the risk factor for excess mortality, cut-off points for obesity (based on the BMI) could be different for different populations and as a result, population-specific (rather than general) cut-off points have to be defined."Commenting on a report claiming that more than half the players in the National Basketball Association are overweight according to the BMI standard, University of Louisiana researcher George Bray argued: "No one has ever suggested the BMI is the only criterion to use." And yet [the BMI is] the only criterion used by government regulators who claim that 65 percent of Americans are too fat. And, unfortunately, nearly every study that attempts to assess the health consequences of obesity or the cost of obesity uses the BMI.
"We have stopped the epidemic of obesity. Between 1999-2000 and 2001-2002 there were no significant changes among adults in the prevalence of overweight, obesity, or extreme obesity."
—Journal of the American Dietetic Association, 2005