I’d like us to ditch all talk of BMI as a meaningful measure when it comes to individuals. And please don’t say it’s better than weight because it’s just weight + height taken into account. So insofar as weight is a problematic measure and BMI relies on weight, so too is BMI problematic. I’ve long loved Kate Harding’s project BMI Illustrated over at Shapely Prose. She describes it this way, “I put together a slideshow to demonstrate just how ridiculous the BMI standards are.” This isn’t to deny that BMI talk is useful about populations and big picture trends, it’s just that I think it’s misleading and harmful when it comes to individuals.
Lots of thin people are falsely reassured by their BMI, while lots of people with BMIs in the overweight/obese categories might be worrying with no good reason. Fit and fat are linked but not in the ways most people think. I worry that lots of fat people don’t exercise because they worry what people will think especially if you exercise and don’t get any smaller. Yet fat and fit people can be very healthy. “People can be obese yet physically healthy and fit and at no greater risk of heart disease or cancer than normal weight people, say researchers.The key is being “metabolically fit”, meaning no high blood pressure, cholesterol or raised blood sugar, and exercising, according to experts. Looking at data from over 43,000 US people they found that being overweight per se did not pose a big health risk.” reports the BBC.
I love my family doctor who cheered me up immensely when she looked at my chart and said, “This is the part of the visit when, given your weight, I should warn you about the health problems associated with overweight and obesity. However, given that you’ve got low to normal blood pressure, no sugar issues, and the best ratio of good to bad cholesterol we’ve ever seen at this clinic, I can’t in good conscience do that. You’re extremely healthy. Whatever you’re doing, keep doing it.”
A few years ago I tried Weight Watchers–for probably the 6th time in my life, will I never learn?–and I was shocked at their weight range for my height. Weights I haven’t seen since Grade 6. And to give you some perspective they were also weights I never weighed even when at 5’7 I wore size 8 clothing. The so called “healthy” or “normal” weight range for me has never seemed plausible. I had an interesting experience recently. This summer I was measured in the BodPod at the Fowler Kennedy Sports Medicine Clinic which tells you exactly how much of your body is fat and how much is muscle, bone etc. I was happy to see that to weigh what Weight Watchers thought of as my ideal, I’d be allowed a mere 20 lbs of body fat. I won’t discuss exact weights today but I will tell you that I’m 122 lbs not fat. It’s my goal as part of my ‘fittest at fifty’ plan to improve my ratio of lean body mass. You can read more about the difference between the BMI approach and the lean body mass approach here. I plan to both develop my muscles and lose some body fat. I’d also like to lose pounds in absolute numbers too, mostly though to make running easier on my joints and to make it easier to get up hills faster on the bike! Hill climbing on the bike is all about power to weight ratio and so I’ll never be a climber but I hate to get dropped on hills on a regular basis. According to BMI, I’ll likely always be overweight or obese and I’ve made my peace with that. (I’ll write more about my ambivalence around ‘fat’ as a label for me later.)
Marc Perry notes in Get Lean that according to BMI most American football players count as obese. So too do many Olympic athletes. There is list here of all of the Gold medal athletes from the 2004 Olympics in Athens who count as overweight or obese according to BMI. We need to change our image of what athletes look like. Usually they don’t look like fitness models. See Howard Schatz and Beverly Ornstein: The Different Body Types of Olympic Athletes.