Why your BMI doesn't really tell the whole story...

CoryIda
CoryIda Posts: 7,870 Member
edited September 27 in Fitness and Exercise
I am living proof that BMI isn’t always a good measure of health.
I’m 5’10” with a large build and currently weigh 195 pounds. By all accounts (except my BMI), I am fit and healthy.

fullbody194-1-1.jpg

Waist to hip ratio: 0.73
(low risk/healthy. Anything under 0.8 for women is healthy)

Body fat %: 26.5
(“Acceptable,” which is between 25-31% for women.)

Waist size: 30”
(anything over 35” or ½ your height in inches increases risk of diabetes, heart disease, etc.)

BMI: 27.98
("Overweight" by more than 20 pounds - “Healthy” BMI Range based on my height: 128.9 – 174.3 lbs. Middle would be 151.6 lbs)

Now, let’s just do a little math. Based on my current body fat %, I have a little over 142 pounds of lean body mass (bones, blood, muscle, etc.). I literally could NOT weigh 128.9 lbs even if I starved myself.

To reach the middle of my “healthy” BMI, 151.6 lbs, I would be left with only 9.6 lbs of body fat, which is around 6.3%. That isn’t healthy. Even if I was an Athlete, my body fat % really shouldn’t fall below 14-20% and, to be perfectly honest, I’m not an athlete.

I exercise (obviously, or I would undoubtedly weigh less based on my measurements), but I’m not – and don’t really want to be – an athlete. I like having curves and a little softness.

So, taking into account the fact that I am not an athlete, the next level up is “fitness” – for a woman to be within the fitness range for body fat, they should have between 21-24% body fat. Let’s say I want to go for the middle of that of 22.5%.

If I don’t gain any more muscle (which would make my lean body mass go up), then I would only need to lose another 9.5-ish pounds of fat to reach that number, leaving me at just over 185 pounds – more than 10 pounds “overweight” according to my BMI.

My point?

For some people, BMI can be helpful but it definitely doesn't tell the whole story. Focus on being fit and healthy, regardless of what the scale – or the chart – says.

Replies

  • jeffrodgers1
    jeffrodgers1 Posts: 991 Member
    I hear you... I am obese at 5'11" and 225 lbs. BMI claims I should be 155-165 lbs. I could use to lose 25 lbs... but would need to amputate a limb to reach 165.

    BMI fails to take into account what is muscle and bone vs what is fat.
  • erickirb
    erickirb Posts: 12,294 Member
    So, taking into account the fact that I am not an athlete, the next level up is “fitness” – for a woman to be within the fitness range for body fat, they should have between 21-24% body fat. Let’s say I want to go for the middle of that of 22.5%.

    If I don’t gain any more muscle (which would make my lean body mass go up), then I would only need to lose another 9.5-ish pounds of fat to reach that number, leaving me at just over 185 pounds – more than 10 pounds “overweight” according to my BMI.

    FYI, while losing enough weight to drop to 185, you most likely will also lose muscle. When losing weight you lose muscle at fat so at 185 you may be more like 24% BF not 22.5%. In order to get to your 22.5% you will probably be more like 175-180lbs depending on how you lose the weight. The slower you lose the less muscle you will burn while losing. But I agree with you about BMI.

    BMI was not designed as ideal weights, it was designed to compare 1 group vs another, in other words looking at a group that has a BMI over X typically have more Y than a group that has a BMI under X. Doctors started misusing it fist and now it is everywhere.
  • CoryIda
    CoryIda Posts: 7,870 Member
    So, taking into account the fact that I am not an athlete, the next level up is “fitness” – for a woman to be within the fitness range for body fat, they should have between 21-24% body fat. Let’s say I want to go for the middle of that of 22.5%.

    If I don’t gain any more muscle (which would make my lean body mass go up), then I would only need to lose another 9.5-ish pounds of fat to reach that number, leaving me at just over 185 pounds – more than 10 pounds “overweight” according to my BMI.

    FYI, while losing enough weight to drop to 185, you most likely will also lose muscle. When losing weight you lose muscle at fat so at 185 you may be more like 24% BF not 22.5%. In order to get to your 22.5% you will probably be more like 175-180lbs depending on how you lose the weight. The slower you lose the less muscle you will burn while losing. But I agree with you about BMI.

    BMI was not designed as ideal weights, it was designed to compare 1 group vs another, in other words looking at a group that has a BMI over X typically have more Y than a group that has a BMI under X. Doctors started misusing it fist and now it is everywhere.
    Technically true; however, when I started (at 280 lbs), I had about 150 pounds of lean body mass. In 85 pounds, I've lost only about 7-8 pounds of muscle. I doubt I'll lose much more in the last 15 pounds; however, even if I did end up with a body fat % of 24, that is still in the "fitness" range and, as it is, I'm already on the lower end of "acceptable," which is perfectly healthy.
  • Chicka_Boom
    Chicka_Boom Posts: 62
    Like erickirb said, the Body Mass Index was not designed to evaluate individual health or fitness levels - it was created as a way of comparing populations. It is considered an effective way to measure poverty, as body weight is less prone to measurement errors than income. It is used by social scientists to evaluate the relative poverty and malnutrition in geographical areas, and to compare segments of a population (for instance, women vs. men or people living below the poverty line vs. people living above it).

    What I'm saying is basically - you're right. Your BMI doesn't tell the whole story.. because it was never actually meant to tell a story about your individual health. At some point, loads of people - even doctors, who should know better - began using it as the standard metric for determining obesity, completely ignoring the fact that it does NOT factor in things like bone density, musculature, and body composition. It can be okay for getting a general idea of where you are if you must use it, but once you see that there are amazingly healthy athletes who are considered "overweight" based on their BMI you realize that it's not really effective for individuals.

    You've made awesome progress, and you're right to ignore your BMI. Your body composition and overall fitness and health are what's important - keep up the good work!
  • themommie
    themommie Posts: 5,033 Member
    I dont care what the BMI says but i want your measurements. LOL You have done amazing, you look great
This discussion has been closed.

Categories