Oh, sweet merciful mother of God:
The Defence Force has announced it will restrict sugary fizzy drinks and deep fried food as it emerges more than a quarter of its personnel are ‘obese’.
This story frustrates me so. I’ve criticised the use of BMI as a “health” metric for years, and the response is always the same: “Oh, but it’s a good measurement for populations as a whole.”
It simply makes no sense. If a metric doesn’t tell you anything useful about someone on an individual basis, what can it possibly tell you on a population-wide basis?
It might provide some information on how the population’s average-weight-divided-by-square-of-height is changing over time, but that’s equally meaningless in terms of “health”. Different ethnic groups have different body shapes (and different health issues). Older populations have different body sizes to younger populations (and different health issues). Why not measure those things when we’re talking about how healthcare costs are changing over time?
And what the apologists ignore is this: BMI is most frequently used against individuals. Immigration, access to certain types of healthcare, forcing fat people to buy two plane tickets: they target individuals for demeaning, inadequate, even harmful treatment, every time.
The supreme irony is that I’ve often challenged BMI-is-good-for-populations by saying “but how can it be a good measurement if you can’t even say for certain whether a high-BMI population is [a group of lazy fatties] or [a group of weightlifters]?”
And there is sneering and eye-rolling about how unlikely it is that NZ’s population-wide BMI is going up because more of us are weightlifting.
Well, here you go: a quarter of our military personnel are obese, compared to a third of the NZ population overall (according to the Ministry of Health, which also thinks BMI is good for anything). That’s a much smaller gap than you’d assume if you remember that the military is meant to be younger and fitter and the general population older and More Evil less fit.
(Of course, our military, especially our Army, is also a lot browner than the general population – remember what I said about different ethnic groups and different body shapes?)
We can either assume that our military training has really gone off the rails, or – hold onto your hats – that BMI, as an individual measurement, as a group measurement, is totally worthless for determining anything at all.
And next time you see an article screaming blue about how our “obesity rates” are “out of control”, don’t picture a gross, headless fat person holding a burger. Picture Richie McCaw, whose BMI, at 30, means he’s being counted as one of the terrible fat people destroying our health system.
~
PS: And of course, Stuff just couldn’t resist including a picture of Minister of Defence Gerry Brownlee, because get it, LOL, he’s fat.
Stephanie Rodgers 