BMI - how good it is for determining health risks/whether a person is obese?

Hey guys! Hope you're all well :)

I was just surfing around online and read something that says the average American woman is 164 pounds and a size 14.

WOAH! I'm like, 5 foot 4, 182 pounds and a size 10/12. That means the average person weighs like 20 pounds less than me and has a larger waist??

So I decided to check with BMIs, because I've heard that's a good scale to determine how healthy someone is. I already knew about what mine was, 31.2 (obese). I don't know the average female height so I just guessed 5 foot 6, and a person that tall at 164 has a BMI of 26.5, which is just over weight! And on the lower end! That's a really big difference, 4.7 points!

I don't consider myself an obese person at all, but looking at my stats always makes me feel like I am obese. I mean yeah I can afford to lose some weight and I'm currently doing that, but I'm in pretty decent shape and I don't feel like my weight is going to cause health issues, but I thought obese people usually had health issues. 

How much importance should I put on the fact that my BMI says I'm obese? Is that the be-all-end-all, that if your BMI is 31.2 you need to lose weight in order to be healthy? Any information is greatly appreciated!!! :)

BMI doesn't address health at all.  there are lots of better indicators (waist circumference, body fat %age, cardiovascular fitness, etc) but no one is the be-all and end-all.

can you run a mile?  do ten push-ups?  i think that what our bodies can do is far more important than the dimensions.

The BMI is a very good 'early warning system'.  In vast majority of people with an 'obese' BMI it's likely they have got to that point through a combination of overeating, making poor food choices and not being active enough.  It's also a good predictor of future long-term health prospects.  Young people can be very overweight and it may not affect how healthy they are short-term.  Same applies to smoking, drinking and other poor lifestyle choices..... they don't kill you tomorrow or next week, it takes years for the damage to accumulate.  However, the longer you remain obese, the much greater your chances of developing heart-disease, cancer, Type II diabetes, gall-bladder problems, hypertension.... all kinds of nasty and largely preventable problems. 

Glad you're losing weight.... it's a smart move.

Thanks for the answers guys :)

pgeorgian, I used to (in like January) be able to run 4 miles at a time, but then I started playing water polo for 1 1/2 hours at college 6 days a week and didn't run at all unless we had a day off, and since that's ended I've re-started running and just got back to 2 miles yesterday, with plans to try to make at least a 10 K by the end of summer. I can do 10 push ups, if I really try at it, and I'm actually working on that as well.

You're definitely right though, gi-jane. I still need to work on the weight. I think it's mostly with what I eat because I'm definitely active enough, I'm going to continue to work on that.

Thanks again!! :)

Original Post by prep_girl_nessa:

I think it's mostly with what I eat because I'm definitely active enough, I'm going to continue to work on that.

 This is where something like CC comes in useful.  Many people find themselves overweight despite being very active and eating a relatively good diet.  And those people almost always discover once they check the calorie content of their foods that they are simply 'eating too much'...   So if you invest in a food scale and keep track of your portion-sizes and calorie intake for a few weeks you'll be able to see how much food you need to achieve and maintain a lower weight.  I discovered, for example, that what I thought was a normal-size portion of pasta for one was actually enough for two! 

BMI is a good general guideline to health risks. Not the end-all-be-all though.

Some recent research shows that many health risks commonly associated with obesity are actually more related to cardiovascular fitness and waist circumference (waist circumference less than 35" is 'good'). Waist to hip ratio is also important. If your waist is considerably smaller than your hips, you can carry more fat and still be considered 'healthy.'

BMI doesn't take the weight of muscle into consideration, it assumes that most of your weight is fat. So if you are muscular, you're BMI will be higher than normal. I agree with pgeorgian, get you body fat percentage checked for a better idea.

Original Post by prep_girl_nessa:

I don't know the average female height so I just guessed 5 foot 6,

 I read in an article, the average height is 5'4. That might be UK not USA but really they probably have the same average height.

Good replies here.  Yes, BMI is important, but there are other factors.  For instance, I am currently 5'1" 115, which is a good BMI (21.7), but my waist is 28 inches.  No matter what weight I am at, I consistently have just an eight inch difference between my waist and hips.  I have 36 inch hips right now (which in itself is a limited term as I don't really have much in the hips at all - it's mostly the backside, lol).  When I was at a 30 inch, my hips were 38.  When I was at a 27 inch waist in my skinniest days, my hips were 35.  I just seem genetically inclined to the avocado body shape, i.e. just barely under the 0.8 waist-hip ratio.  This isn't ideal for health reasons, but I've been unable to reduce the waist without reducing my hips/backside at the same time.

To kdm1984 have you tried a 'clean' diet?.... Sometimes a thick waist measurement in an otherwise slim person can be indicative of fluid retention and the main culprits are processed foods, excess salt in the diet, caffeine, alcohol, sugar, artificial sweetners etc.

Fluid retention just may be it..even when I've cut back on salt, caffeine, and whatnot, I never drink enough water anyway.  I am probably retaining what little of it I take in since I only get thirsty and drink fluids when I eat.  I definitely get nowhere near the recommended 8 glasses of water a day.

I think BMI is indicative of health risk only at the extremes. The correlation with ill health is just not very good, and there are better metrics out there.

There is nothing to indicate that people in the "normal" category are any healthier than people in the "overweight" category. I believe very high BMIs *do* correlate with poor health, because they correlate somewhat with sedentary lifestyles and  food intake that is not nutritious.

I do think BMI may be useful to some, if it serves as a wake-up call to a better lifestyle. Some people are fooling themselves they do enough exercise and eat well, and they don't. But it cuts both ways, I think. I'm a "normal" weight. I know I'm not doing enough exercise. I know I'm not making the best food choices all the time. But when I go to the doctor, he/she doesn't bring up exercise and diet. I could quite easily fool myself that I'm doing everything right. I'm not.

This thread was from June.