What's Your BMI? Why Does It Matter?

Below is a guest post by Annie Lynsen, on loan to AARP from Small Act.

I was lucky enough to be built like a twig in high school. Mistakenly, I assumed I would always stay that way - eating what I wanted, not exercising, and letting all the calories just melt away naturally.

But after a couple of years of living a fairly sedentary lifestyle, cooking all my favorite foods (especially baked goods), and working at a place that offered a never-ending parade of doughnuts, cookies, chips and candy, I noticed I was getting a bit curvier.

I wasn't too concerned. I bought bigger pants, shunned the scale, and decided not to worry about it. After all, I didn't want to become one of THOSE women - the type who obsess about every calorie they consume.

And then reality hit me one day when I was in my mid-twenties. I received a free copy of the Mayo Clinic Guide to Self-Care at a work conference, and read up on how to calculate one's Body Mass Index, or BMI. Your BMI is an estimate of your body fat that is based on your height and weight, and can help doctors determine your current state of health and potential risk factors.

I dusted off the scale, stepped on it, and ran the calculations.

"That can't be right," I thought, and ran the calculations again. But it was true: my Body Mass Index was solidly in the "overweight" category.

That was the day I decided to change my lifestyle. I started walking for half an hour every night after work, and bringing healthy snacks to work to eat when I was tempted by cookies and candy. And it worked - slowly, the weight came off, and I got back down into "healthy" BMI territory after a year.

And I'm pleased to report that the habits I cultivated then have stuck with me. I still gravitate toward healthy snacks and exercise about five days a week.

Just as it's important to have annual check-ups, it's important to keep an eye on your BMI once in awhile. But how do you calculate it? I'm glad you asked.  Check out AARP's BMI Calculator.

Have you calculated your BMI? Did you make any changes to your lifestyle as a result? Share your story in the comments.

Photo credit: Annie Lynsen