Article Link The Problem with BMI (Body Mass Index)

[frostyjan]

Hi to all,

This is an interesting article that explains the problem with using BMI as a measure of health risk.


https://bigthink.com/health/healthy-obesity-myth/

[Leonana]

Interesting article. I’m 5’7” and wear a size 12-14. I’m not thin but most people don’t consider me overweight. My recent BMI from my last doctor visit was 25.5, which labels me as obese. However, I guess it doesn’t take into account my muscle, and I’m bigger boned with large shoulders. Plus, I’m weighed while wearing heavier jeans and shoes, and I imagine that could change slightly when you are weighed in summer with lighter clothing.

According to the article, I’m in the healthiest group. My doctors never have mentioned my weight, so I guess my BMI isn’t an issue for them.

[prettyinpink]

Good article.

This is the part I found most interesting.

When a team of researchers adjusted BMI to take muscle mass into account back in 2018, then associated this corrected measure with mortality risk, they found that the “U” mostly transformed into a straight line. Extremely obese individuals went from having only a marginally increased risk of death compared to healthy individuals to about a 70% increased risk.

From other sources, mortality may be the lowest at BMI 20-23, then begins to curve upward. Well, human mortality is 100% for everyone, but earlier mortality, I guess you’d say. I understand some work has shown it is different for older vs. younger, that more weight is not as risky for the elderly.

But doctors don’t have an easy, quick way to assess for muscle mass in the office. On the barbell medicine podcast, and of course many other places, it was mentioned that waist circumference is thought by some doctors to be a better way of assessing metabolic risk, but the research on that is not extensive like the BMI research. And most of us already don’t love being weighed, so measuring the waist may make people even more uncomfortable. I had it done once and it did feel a little too much in my personal space. For a doctor’s office it’s really not, but we aren’t used to it. BMI is not perfect at the individual level, but the average person does not have a large muscle mass. The classic example is the male bodybuilder or athlete who is very big but extremely lean with a sub-10% body fat; we don’t know that that person has greater risks just from falling into the “obese” range.

For an individual person, it’s a potential risk factor like high cholesterol, not an absolute predictor. It’s a population-level tool that they think can be useful, but is more complicated when applying to one person.

Leonana, obesity is 30 or higher.

[Leonana]

prettyinpink, I didn’t know that. I had read it was over 25, but perhaps that is outdated information.

Of course, genetics makes the biggest difference. I have a progressive kidney disease and will probably be on dialysis in my 70’s. I’m trying to stay as healthy as I can now so my body will be stronger to handle it.

[prettyinpink]

I’m sorry to hear that.

I did find this article in which some researchers thought that the cutoff for obesity should be lowered to 25 for postmenopausal women, and they explain why. But it seems like that wouldn’t apply to someone who has been exercising for years and might not have the higher body fat levels of some of the women in the study.

https://jamanetwork.com/journals/jam...rticle/2674709

[Gemini2874]

Another take: https://open.substack.com/pub/katema...utm_medium=ios

[frostyjan]

Originally Posted by Gemini2874

Another take: https://open.substack.com/pub/katema...utm_medium=ios

Interesting article about Oprah, but I wouldn't call it "another take". The point of the linked article is that BMI is a terrible way to assess health risks.

[Gemini2874]

This will be my last post to you as we will just have to agree to disagree about “the obesity epidemic”.

[Jane P.]

I was overweight when I began serious exercise several years ago. I gained a fair amount of muscle and a good low pulse, but my doc did not believe me, and nagged me about my weight. It definitely wasn't the same body as before I started exercising but the BMI was the same.

Now my BMI is about 25, but I don't have as much muscle as I did then. I doubt I would be nagged about my weight now.

[Leonana]

Originally Posted by prettyinpink

I’m sorry to hear that.

I did find this article in which some researchers thought that the cutoff for obesity should be lowered to 25 for postmenopausal women, and they explain why. But it seems like that wouldn’t apply to someone who has been exercising for years and might not have the higher body fat levels of some of the women in the study.

https://jamanetwork.com/journals/jam...rticle/2674709

Thanks.

Wow, lower than 25. Losing weight is harder after menopause, so would be difficult for some women.

It seems there is an exception for physical activity.

Numbers don’t tell the whole story. “Regardless of what the cut point is, there will be a lot of individual variation in terms of what the BMI means,” she explained. Manson said she prefers to focus on lifestyle behaviors rather than weight, per se. If a postmenopausal woman is physically active and her waistline hasn’t changed much over the years, Manson said, she probably doesn’t have to worry that her BMI of 25 might be too high. “I always think about physical activity as the magic bullet of good health.”