MICHAELA GIBSON MORRIS: BMI beats down best intentions

By Michaela Gibson Morris

I’ve got a bone to pick with BMI.
Body Mass Index – which turns height and weight into a single number – was designed as a screening tool to track weight. You have to hit between 18 and 24.9 to be considered having a healthy weight. And way too many of us, especially in Mississippi, are well over 25.
BMI doesn’t just tick me off because – as you can tell from my column mug – I’m at the wrong end of the scale.
As a tool to judge where we stand as a population, it’s probably a pretty decent tool for judging the obesity levels of adults. It has the benefit of being something relatively quick and easy to measure, which is why it’s so widely used. But it’s just one measure of health status.
My specific issue is that it seems like far too many people look at BMI as the whole puzzle.
BMI has acknowledged shortcomings. It overestimates the body fat of athletes, which is why one of my very active coworkers can’t get his BMI within shouting range of healthy, even though he works out nearly every day and has taken up running.
It also underestimates the body fat of the thin and inactive. So they get a pass from BMI, appearing more healthy than they likely are.
In the news last week, a newly published study found that otherwise healthy people who are overweight are at 13 percent higher risk of mortality than people who fall in the healthy range.
My problem is not with the study. Good clinical studies aim to zero in on very specific questions. The researchers sought to focus in on an answer for a very specific question: In otherwise healthy people, does being overweight increase your risk of dying?
My problem is how I fear people will interpret this study: If you can’t get below 25 BMI, you might as well not even bother.
There’s no arguing that carrying too much weight is a real, significant health risk. Heart attack, strokes, many kinds of cancer, arthritis and diabetes are all linked to carrying too much weight.
But we need measures that encourage people to begin and maintain the process of creating a healthy lifestyle, not measures that leave them hopeless.
BMI doesn’t recognize the good work of someone who has started walking 20 minutes a day and has kept it up every day for six months. BMI doesn’t recognize the person who has dropped 10 percent of his or her body weight in the past year and kept it off.
I’m not advocating that we should ignore BMI. I’m just asking for ways that more of us can find success, so we can live longer, healthier lives. Please.
Michaela Gibson Morris is a Daily Journal staff writer. Contact her at (662) 678-1599 or michaela.morris@djournal.com.