I'm confused about the body fat percentage and BMI thing?

Question

well I'm 13 years old, 5'4, and 140 lbs; in gym class we used these machines that you enter your height and weight and age in and it tells you your body fat percentage; well it said i was 30.5 %. but then a week later, we determined it mathematically, and it said i was 24.6 % body fat. i told my teacher and she said that the correct one was 24.6 % body fat. my question is: am i normal/average? i know im not fit. im like a size 9 in pants and im fatter than most of the other girls in my grade [8th]. my teacher said "oh no; i can tell just by looking at you that your not 30 % body fat" so im not sure what to make of that.. also:

*how can i become more flexible?

Answer 1

BMI and bodyfat are two different things. BMI is useless as it all is does is compare your height and weight to others but does not account for how much muscle you have. For example, an anorexic that weighs 100 lbs may have 32% bodyfat. The BMI chart will say they are healthy. They are not, they are fat. On the other hand a person can lift weights for many years and be 200 lbs of solid ripped muscle and the BMI chart will say they are obese. Every knucklehead that posts a link to the BMI chart or somehow kids themselves into believeing that a good BMI level means they are fit is just not educated in fitness.

Bodyfat needs to be tested by a professional using calipers or water displacement (there are other methods). Those scales and again website charts are notoriously innaccurate.

The bottom line is that at 5'4" 140lbs you could either be in great shape with a good amount of muscle of you could be very flabby and out of shape. There is no way to tell without seeing you.

Answer 2

you're in the acceptable range. the range is generally higher for women because they have more fat. to become more flexible, you'd have to stretch daily. it comes to you over time. and the link the guy had about the BMI thing is generally right. theres no dirfference in BMI charts.

Answer 3

Heres The BMI Chart:

18.5 Or Less- Under Weight

18.6-24.9 - Normal

25-39.9 - Obese

40 Or Greater - Extremely Obese.

Your Close To Obese. I Would Suggest Going To 22.

Lose Body Fat By Running Or Jogging.

Heres The Site:

Http://www.consumer.gov/weightloss/bmi.h...

Good Luck!

Answer 4

Maybe get yourself some callipers. I'm female, 24% body fat and look fairly lean. At 5ft4 and 140lb to have only 24% body fat you would have to have a good amount of muscle from working out. If you are not fit, then it's likely to be higher than this.

For a girl your age the body fat percentage should be between 19%-27%, so 30% is a bit high but NOT obese.