When you’re a kid, you can’t wait to grow up. As soon as you’re tall enough, you can ride the bigger rides at amusement parks. As soon as you weigh enough, you can stop riding in a car seat. Many childhood milestones are marked by reaching certain points of growth.

Today, most doctors help parents keep a close eye on their children’s growth. Not only do they want to make sure you’re growing properly, but they also want to make sure you’re not growing too quickly.

Given the many scientific studies that have linked weight with various health risks, doctors especially want to make sure your weight stays at a healthy level. Stepping on the scale isn’t the only way doctors can keep an eye on your weight, though.

Many doctors now routinely calculate your BMI in addition to your weight. BMI stands for body mass index, which is a calculation that uses your height and your weight to estimate the amount of body fat you have.

If your BMI is too high, doctors will likely be concerned. Having too much body fat can lead to various illnesses and other health problems. A high BMI may be a sign that you need to eat healthier foods and exercise more often.

Although you can roughly calculate your BMI if you know your height and your weight, it’s best to have a doctor do it for you. Since kids are still in the process of growing and age can be an important factor, too, your doctor will be able to calculate your BMI more accurately.

Based upon your BMI, you’ll fall into one of four categories: underweight, healthy weight, overweight, or obese. Based upon the category you fall into, your doctor can make recommendations for any changes you may need to make.

It’s also important to remember that BMI is only one factor to consider with regard to your weight and your health. For example, athletic kids who are very muscular might weigh more and have a higher BMI, yet not have much body fat either. Likewise, a nonathletic child might weigh less and have a lower BMI, but still have too much body fat.

If you have too much body fat, you probably don’t feel as good as you could. Too much body fat can make it harder to do many things, from sleeping to breathing to exercising. To feel your best, get your BMI checked by a doctor and follow all diet and exercise recommendations.

32 Join the Discussion

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  1. I am one of those athletic kids because I do cheerleading, gymnastics, and basketball. I have never heard about BMI so you just taught me a lot of new things.

    I think tomorrow’s wonder will be about Thanksgiving, or what are beets.

    • That’s great, Wondergirl101! It’s important for all of us to exercise and stay healthy! We are all different shapes and sizes, but being healthy is SUPER important! We’re glad to hear that you enjoy participating in all sorts of sports! How great! :)

  2. I liked today’s WONDER. I went to my physical and found out I was underweight. I was at a BMI of 19 or something. I just blame the metabolism for that.
    I think tomorrow’s WONDER will be about the history of Rock and Roll.

    • Hey there, Emily! We are glad that you are WONDERing about your BMI with us! It’s great to learn about different things that affect your health, weight and body! :)

  3. WOW! We just learned yesterday from the gym teacher that we need 20 minutes of activity each day to stay healthy. We think that will help our BMI.

    • What a great connection to today’s Wonder! We’re excited that our Friends in Mrs. Utter’s Kindergarten Class are staying healthy with exercise and good food choices! We LOVE when exercise is fun! Thanks for sharing your comment today! :)

    • He he, you make us smile, Minecrafter! Thanks for sharing your comment with us! While the color black is slimming (you’re right!) it’s also best to live a healthy lifestyle! That way you’ll be smiling all day long! :)

    • Way to go, Wonder Friend Danielle! We sure are glad you learned something new with us at Wonderopolis today! Staying healthy is a SUPER way to feel great! :)

  4. Wow! I’ve also learned that if you exercising can increase your lifetime! How interesting is that? This is another fantastic wonder on your pages! Well done!

    • Gosh, thanks so much, Simon! We’re so happy to hear that you enjoyed our Wonder about your health! It’s so much fun to Wonder with you! :)

  5. Thanks so since I know that then I know that I’m going to have a wonderific life because I dance at Dance world!!!!!!!!!!!!!!!!!!!!
    Sincerely Danielle :) :) :)

  6. I play all different sports and spend hours everyday exercising but my BMI is extremely high, but I have little to no body fat. Also, how do you keep the site running? Are you paid? Or is it a hobby?

    • It sounds like you have a lot of muscle, Isaac! That is fantastic! If you are concerned about your BMI score, you may want to check with a doctor or school nurse to make sure that you are calculating it correctly.

      Wonderopolis is part of a non-profit organization that depends on donations from the public and from corporations. Check out this Wonder about non-profits:

      Wonder #1120: How Does a Nonprofit Work?

      Enjoy, Wonder Friend! :-)

    • I’d like to add that there is also a “density” factor, I think with bones. I’ve done face painting for years and I can tell you, in lifting toddlers into the chair, you canNOT tell, by the look of them, how much they weigh. Some children are very “solid” and heavy, while others are almost as “light as a feather,” neither child being overweight by appearance. These tools are a “guide” as to whether or not you have a weight problem. That’s my opinion, anyway.

      • Thanks for sharing your opinion, :Donna Marie! We agree, the BMI is one of many tools doctors use to assess the overall health of children and adults, and there are cases that don’t quite fit neatly in one of the categories. It’s best to use the tool with your doctor’s guidance to ensure you’ve got an accurate picture of your overall health! :)

  7. hai, i have one doubt if persons like bodybuilders, for example “Arnold Swagznegar”, Dwayne johnson, Brock lesnar and so on, their weight would be more than 110 and i guess their BMI would also be over weight or else something . Do they need to reduce their weight to avoid illness? or Do they encounter any problems like fatty persons?

    • That’s a good point, Madhavan! People who are bodybuilders might not fit within in the “healthy” category of the BMI because of the weight of their muscles, but they may still be quite healthy overall. We imagine that those people probably work with their doctors to ensure they’re maintaining good health. :)

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