I just joined SparkTeens, because I need something to help keep me on track (along with this fabulous website, of course). But they seem to have a different BMI scale than other websites. From at least 3 other BMI calculators, I determined that weighing 145 lbs at 5'4'' would put at 24.9 BMI, right at the end of the "Healthy" range. So I thought, okay, I'll make that my first goal. But when I put it into the SparkTeens BMI calculator, it said I would still be overweight! D= It turns out that their "Overweight" range goes from 24.6 to 28.8.
So have I been using the wrong calculators? I know that none of them are completely accurate, but all the other ones I used said 145 would be healthy for me-- given, it's the borderline healthy weight, but still. Could the fact that I'm under 18 have anything to do with it?
Thanks for reading, I know this seems like a silly thing to get upset about, but I'd like to know if I'm chasing an unrealistic goal...
Make sure you're not confusing BMI, which is based on nothing but your height and weight, and thus should always be the same anywhere, and body fat percentage, which can't be measured so easily.
The numbers for overweight and obesity for BMI and body fat percentage are not the same. And obviously two people can have the same BMI and very different body fat percentages.
Although, I suppose anybody could make up their own normal and overweight ranges. But the ranges for BMI are pretty standard (overweight at 25.0, obese at 30.0). Body fat ranges are a bit more subjective and variable.
Yeah, I just checked again, all of the ones I used were BMI, not Body Fat Percentage or anything else. I thought the measurements were pretty standard too, which is why this confuses me even more. :\ Maybe it's to encourage people to lose more weight or something... I dunno.
I don't even look at BMI to be honest. According to my BMI I should weight like 150-170 lbs MAX. I currently weight 219, my lowest was 190. I'm 5'10". Even my doctor said trying to maintain 170 lbs at my height and body type would be next to impossible. Do you have a doctor? They may be able to help you find a good goal.
i think the website is a little quacky to change the Medical Values for BMI.
which as another poster stated was 18- 24.9 Normal; 25-29.9 overweight; 30 + obese.
The reason you got a different result from SparkTeens is because BMI ranges are different for children and teenagers up to age 19 and you said that you were under 18. Everyone is right that 24.9 is the cutoff for adults, but it's not for teenagers. SparkTeens' calculator must use the different ranges based on age, which is why you came up with a different result than the adult BMI.
If you're pretty close to being 19, I'd say just use the adult BMI charts and ignore the teenage results. They're awfully close anyway.
Is BMI interpreted the same way for children and teens as it is for adults?
Although the BMI number is calculated the same way for children and adults, the criteria used to interpret the meaning of the BMI number for children and teens are different from those used for adults. For children and teens, BMI age- and sex-specific percentiles are used for two reasons:
* The amount of body fat changes with age.
* The amount of body fat differs between girls and boys.
The CDC BMI-for-age growth charts take into account these differences and allow translation of a BMI number into a percentile for a child's sex and age.
For adults, on the other hand, BMI is interpreted through categories that do not take into account sex or age.
As Meg says, there are specific calculators for children/teens. Whilst the sum is the same the interpretation of the result is different dependent on age. I wouldn't sweat it however. Aim for a weight that is comfortable for you. My BMI is still classed as "overweight". However my fat% is within normal range and my muscle mass is higher than would be expected for my age/size so I'm happy with a higher BMI.
BMI for kids/teens is calculated as a comparison to the average kids/teenager of a particular age. in reality, the changes mentioned by meg tend to only apply until puberty is finished. for most girls, you can use the adult calculators by 16 or 17
BMI Woes
