Where BMI Goes Wrong. Lessons From Cupid.

Yesterday was Valentine’s Day and no, I’m not going to flash more food porn involving chocolates. But with Cupid hovering around lately, I couldn’t help but address the subject of BMI, Body Mass Index.

What if Cupid and his parents showed up in my office concerned about obesity, what would I say? Let’s assume for a moment, from the various images of him these days that his BMI was in fact high. For the record, BMI is simply a calculation of weight divided by height squared, used as a marker for obesity. It is not, as you have been lead to believe, a measure of body fatness, or percent body fat.

If historically, as evidenced by Hallmark’s greeting cards, Cupid has always been husky from his youngest years, here’s what I’d say. Assuming he has paralleled the BMI chart, he is gaining as much annually as any other normal healthy child. It’s just that he started larger, simply genetics, most likely. I would still explore his intake and eating behaviors, recommending modifications to ensure health and prevent disease (just as I would do if an average weight individual presented for, let’s say, food allergies). But if all looked well, I would not create a problem where there was none.

If, however, I discovered he was hoarding the chocolates he planned to deliver, binge eating or emotionally overeating, perhaps because of unrequited love, these patterns would need to be addressed—with me, and with a therapist.

Like chocolates, we come in all shapes and sizes. And if your size, like Cupid’s, has always leaned on the larger end of the spectrum, it is likely that is a healthy, and normal place—for you. If, however, you have never listened to your hunger and fullness, tending to regularly use food for comfort or to manage stress and emotions, there’s room for changing your relationship with food, and as a result, your weight.

Maybe as an adult your BMI is out of range, placing you in the “obese” category. That puts you in good company, with top paid professional athletes such as Vince Wilfork and Charles Barkley. BMI is hardly the best way to gauge your size, or your risk of disease. Many with high BMI’s are quite healthy and fit, often at the top of their game. BMI may be high simply from a high muscle mass. Remember, body mass index does not distinguish where that mass comes from—muscle or fat (or bone, for that matter).

Years ago a woman who did body building recreationally came in for assistance with weight loss. It was winter, and quite frankly, visually I could never have guessed what her risk was. By the charts, she was obese, with a high weight for her height. But when I assessed her eating, I could only conclude that she wasn’t eating enough, regardless of her weight concerns. Weeks later, following a half marathon, she reported that she was hospitalized with internal bleeding. Apparently, her percent body fat was so low that there was damage to her internal organs, resulting in the bleed. Yes, body fat does have a function, and cushioning our internal organs is just one example.

But if your weight has been climbing out of a healthy range, and you have not dramatically increased your muscle mass, it may be time to take a closer look—at your activity as well as your food intake and eating behaviors.

And we should be most focused on an individual’s pattern, as opposed to their absolute weight or BMI. I had a teen patient not long ago who presented at the 50^th percentile BMI for age. Great, no? His doctor thought so, and was quite pleased with his healthy place on the chart. But a look at his BMI chart revealed that he had plummeted in a very short period, from a high BMI to “normal”. Unfortunately, this drop resulted from anything but normal thoughts and behaviors around food, but rather the consequence of a full-blown anorexia. And reinforcing how “healthy” his recent BMI was only added flames to the fire.

As for the adult Cupid, waist circumference, or waist to hip ratio, would likely tell me more, suggestive of abdominal fat, and associated with chronic diseases including Type 2 diabetes. A waist circumference above 35 inches (women) and 40 inches (men) it is considered a predictor of increased risk. The waist-to-hip ratio—literally, your waist measurement divided by your widest hip measurement—is also a good predictor of risk. 1.0 or above is greater risk, and desirable is 0.8 for women, 0.9 for men. See http://www.cdc.gov/healthyweight/assessing/index.html

But perhaps the best measure to use would be percent body fat (most accurately determined by underwater weighing, but indirectly measured with calipers or more high tech devices).

And yet I rarely recommend it. Why? Because we really don’t need another measure, another number to fixate on. If your weight is climbing out of range, you’ll know it. Take a look at your eating patterns, and activity. Focus on eating mindfully and separating physical hunger from all the other reasons you eat. Reread some past posts on this blog for more guidance!

And if your weight is above a “desirable” BMI, but has been stable for years, and you have normal blood pressure, cholesterol and blood sugar, let it go. As long as you can comfortably engage in activity to keep you strong and fit for years to come.