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5 BMI Myths You Can Stop Believing
There’s no denying the “fat is bad” mantra has led us to believe loads of things about BMI that aren’t true. Here are five “facts” worth rethinking.

I remember the first time a doctor The Benefits of Spirulina. I was 13 and up until that point had been one of the skinniest kids in my class. But then puberty struck, my hormones went haywire, and I packed on 20 pounds in just a few months. My BMI put me squarely in the “overweight” category. The doctor handed me a food journal and said not to worry—as long as I kept track of every single thing I put into my mouth I could drop those 20 pounds in no time.
Well, I didn’t. As I got older, my BMI just got higher. Now, at 25, I’m what the BMI scale considers “obese.” I eat a mostly healthy diet, walk everywhere, and do yoga as often as I can. I know people much skinnier than me—people with “normal” BMIs—who literally cringe at the sight of a vegetable. Yet, most doctors would tell them they were perfectly healthy and put me on a strict diet.
What gives?
“We so strongly believe that being fat is bad,” says Linda Bacon, Advertisement - Continue Reading Below Health at Every Size: The Surprising Truth About Your Weight. “It’s taught in schools and floods the media.” And that’s not surprising. Study after study finds that being heavy is associated with illnesses like diabetes, heart disease, and Alzheimer’s. But the key word, Bacon says, is “associated.”
According to Bacon, we don’t know for sure that being overweight causes the health problems it’s been associated with. It could be a combination of many things. For example, people who have high BMIs also tend to have a history of dieting, Bacon says. And research has shown that yo-yo dieting, or fluctuating in weight, has a increase in heart attack risk. “So does illness come from having a higher BMI or from inflammation in the blood due to dieting?” Bacon says. “We just don’t know.”
There’s no denying that the pervasive “fat is bad” lens has led us to believe loads of things about BMI that just aren’t true. Here, 5 “facts” you can start rethinking. (Slammed? Even you can squeeze in these feel-good, 10-minute reader-tested workouts!)

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