Is the "Obesity Epidemic" a fantasy?

[brynndragon]

One of the things I noticed when examining the requirements for the study I'll be participating in is the BMI cutoff is 27. Which seems strange because the BMI cutoff for "overweight" is 25. Apparently it *was* 27 until 1998 when the National Heart, Lung, and Blood Institute (NHLBI) decided to make it 25. I can't for the life of me figure out why they made that decision. They state, "The rationale behind these definitions is based on epidemiological data that show increases in mortality with BMIs above 25 kg/m2." with several references. But only one of the references implies that lowering the cutoff might be beneficial (the one that states "available evidence suggests that minimum mortality occurs at relative weights at least 10% below the US average", where the average according to this article (referenced in other places in that NHLBI document) is right around BMI = 25 for women and somewhat above that for men - which makes me wonder why the hell they picked 25). All the rest use overweight = 27 as their basis for making statements about the link between overweight/obesity and morbidity, except the WHO report (PDF). The WHO report doesn't say a damn thing about links between obesity and morbidity/mortality (being focused on malnutrition), nor does it give any specific recommendations at all about where to set BMI even for determination of malnutrition (for which it has good reasons involving the risk of overlooking important aspects of the link between height/weight/age and morbidity/mortality, and translating it into useful intervention, which the NHBLI seems to have completely ignored).

The thing I really want to point out is almost all of the data they use to support the notion that being overweight leads to increased morbidity/mortality involves a BMI >27, not a BMI >25. This might explain why the study I'm participating in uses the 27 cutoff rather than the 25 cutoff.

I probably only care because my BMI is 26. Well, that and the idea that over half of Americans are overweight is based almost entire on this change for which I've found pretty much no freaking evidence. The more I learn, the more dubious I am of our notions of healthy weight. . .

Comments

[cos]

I'm pretty sure there's some of both.

On the one hand, yes, "obesity" is overestimated because we use bad numbers, and many people are considered overweight who shouldn't be.

On the other hand, yes, more Americans are overweight, and more are seriously overweight, than decades ago, and it is a problem.

The idea that you might be in the middle of that - not overweight, but mistakenly classified as such by some measures - makes sense.

[bikergeek.livejournal.com]

My own personal ex recto theory for the change was that 1998 was about when the now-recalled diet drug Fen/Phen hit the market. Arbitrarily declaring millions of people "overweight" or "obese" with the stroke of a pen meant that many more prescriptions could be written.

Just like they keep lowering the bar for what's considered "high" cholesterol so they can keep writing more prescriptions for statins.

Medical "research" these days is driven almost entirely by drug companies seeking to pathologize the maximum number of people so as to maximize their income stream.

This is my burning ball of fury

[metahacker.livejournal.com]

1. BMI absolutely sucks as a diagnostic tool. It turns a cubed-relation into a squared-relation, is based on no experimental data, and ignores frame completely.

We might just as well say you should weigh 2 lbs per inch of height -- it literally makes as much sense, but because it doesn't have a square root in it it doesn't sound sciencey.

2. There is a rampant level of obesity in this country. Travel west of NY or south of DC to see it. The north east is pretty skinny.

3. Using BMI is making it hard to study the problem of obesity. How I loathe that measure.

[rigel.livejournal.com]

. . . over half of Americans are overweight is based almost entire on this change . . .

What percentage of Americans would be considered overweight, d'you think, if this change hadn't been made? (In other words, what percent of Americans do you think are between BMI 27 and 25?)

Also: I'm impressed with your knowledge about such things, and willingness to wade through the citations and numbers. My eyes start to gloss over, and I'm glad someone is.

[robertdfeinman.livejournal.com]

Michael Pollan has a new book out "In Defense of Food" in which he complains about the rise of "nutritionism", that is health claims not based upon any real evidence.

A good example is the rise of "carbs are bad" which may have now been replaced by "fats are bad" advice.

There are now schemes afoot to rate foods using stars or a numeric scale, but there is no objective measure as to what makes a food better. Factoring in things like added vitamins is mostly pointless. Generally speaking people in the US are not suffering from vitamin deficiency, so adding even more to some random product is not going to improve a person's health, but may improve a products "score".

As with all things, common sense and moderation are all that are really required.

[brewergnome.livejournal.com]

Ugh, BMI.

I shudder to think where my BMI has been when I'm doing gymnastics. I know by the even older scale, I just passed into "moderately obese" this past week. Isn't that lovely? Yeah me, "moderately obese."

And the fat that causes the most danger? Not the flab, but the fat that "skinny" people get. The fat around their organs.

[watercolorblue.livejournal.com]

BMI is basically BS. I'm not even going to discuss my number now, but even at my reasonably fit college weight, I was most definitely into the Overweight bracket according to BMI and American standards. I have broad shoulders and an Eastern European build. A lto of it's muscle. There are reasonable goals for my own weight loss, and there's what the government recommends...and they are definitely not consistent with one another.