BMI ≠ Body Image

A recent article on Skepchick makes a critique of Ben Radford’s article on BMI, claiming it’s false that BMI is simply a diagnostic tool: “BMI is often used as a weapon by which to shame, judge, and oversimplify people’s health and wellness.” The author also offers an anecdote about feeling shamed by her doctor for making comparisons between BMIs, and therefore making judgements about body image standards.

The problem is that BMI is not a indicator of how fat you are or the specific measurements of your body. A high BMI is claiming that you are too heavy for your height and age, regardless of whether it’s fat or muscle making you overweight. Consequently, a new study showed that BMI was best, compared to other measuring methods, at predicting health risks related to weight.

Though excess fat is likely the most common cause of having a high BMI, this doesn’t mean the method is making a judgment about body image. Since BMI was a better predictor than body fat percentage or waist ratios, you could take away from the study that it’s being too heavy, rather than simply excess fat, that might place you at a higher health risk. You could have an aesthetically pleasing hip to waist ratio and low body fat percentage, but if you’re carrying too much mass (like muscle) for your frame (height and age), it may cause increased health risks. For example, obesity is now a bigger burden on healthcare systems than smoking.

BMI is a medical tool, and to claim that it is used to shame body image is a weak argument. We tend to judge people’s body image by looking at their waist to hip ratio and how much excess fat they seem to have, rather than their mass. Body fat percentage is likely to place more people in the obese category than BMI, since you could carry a certain amount of excess fat before being considered too heavy for your height.

20130105-162334.jpgI would argue that obesity is the only body image factor that has any scientific validity. Take into consideration the many other beauty standards women are judged by; long legs, waist-to-hip ratio, plump lips, cheekbones, perky breasts, perfect skin, hair, and noses—even plus sized women must meet these standards in order to be considered attractive. However, having thin lips, a big nose, blotchy skin, greasy hair, small or sagging breasts, or a number of other aesthetic critiques of a woman’s image, don’t carry with them the negative health consequences that being overweight does.

Your doctor telling you your BMI is too high is not a critique of your image or attractiveness, but a calculation that you are too heavy for your height and age. This is a valid health critique. Society and media judge women on their visual appearances, not on this calculation of mass, age, and height.

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