I am 5’8″ tall and weigh 165 pounds, which puts my BMI at 25. Healthy normal BMI for men is supposed to be under 25, so my doctor tells me I need to lose weight. Or gain half an inch in height. Either way, really.
I reminded him that the body mass index is only a rough estimate of body composition, subject to a number of limitations and shortcomings, and that the estimate of body composition it provides is itself only a rough estimate of health. I told him I can run five miles at a stretch and that I lift weights regularly. He told me I probably ate too many fatty snacks.
Obviously I went to the gym and asked the fitness expert to measure my body-fat percentage. Her machine told me that it’s 18%. She told me 18% is fine. She also said I should fire my doctor because he doesn’t know the difference between BMI and body composition.
I don’t doubt that obesity is a serious problem. And I’m sure I could be in better shape – my body fat percentage was lower a few years ago, when I was in my 20s and single and exercising every day for an hour or more. But a blind adherence to inaccurate numbers is not going to help things.