Obesity experts warn that the BMI standard suffers from a number of serious limitations in measuring the percentage of body fat—a generally recognized standard for judging true obesity.
"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 [lean body mass], or to any combination of the two."
—Letter in JAMA, June 2005
"The BMI doesn’t give a precise readout. It can be horrible as an individual gauge."
—Cleveland Clinic Foundation Chief Academic Officer and Case Western Reserve University Department of Cardiovascular Medicine Chairman Dr. Eric Topol
"BMI does have numerous limitations that we professionals have chosen to ignore, or at least to tolerate. We have done this on the grounds that its advantages have outweighed its disadvantages. Any expression of doubt over the validity of the key obesity indicator would have undermined the message at a time when politicians and the general public needed to hear a clarion call for action. This herd loyalty to a pragmatic indicator was challenged for the first time by the devotees of waist-hip ratio (WHR) and then by the promoters of waist circumference."
—Obesity Reviews, 2001
"There is increasing evidence that these [BMI] cut-off values are not valid for all populations … If obesity were defined as BF% [body fat percentage] greater than 25% in males and greater than 35% in females, 7% of the females and 8% of the males would be falsely classified as obese with the BMI-based formula."
—European Journal of Clinical Nutrition, 2001
"Our results indicate that a single BMI standard should not be used: rather, a standard should be developed for each population. This conclusion is in agreement with work by other researchers, who also found BMI inconsistencies between groups."
—International Journal of Obesity and Related Metabolic Disorders, 1998