I recently read something that said the main reason people are ‘fatter’ and there are 2x as many overweight people (by BMI standards) today than in 1990 is because in 1990 a BMI of 27+ was considered overweight but in 1998 or so it was changed to 25. This added tens of millions of normal people into the ranks of the overweight, which is why the rates for obesity are said to have doubled.
Is this true?
I doubt that any significant number of people have ever ranked themselves according to the BMI for the BMI to be considered as having any significant inlfuence over staggering numbers of obese people.
Death doesn’t even make a dent the other way.
No, it’s not true (with a qualifier). It is true that the the definition of overwieght changed in 1989 (cite). But, the number of people with higher BMI’s (no matter what you call it) has also increased dramatically over the last twenty years.
For more information on overweight criteria, see here.
While the general population has gotten heavier over the years, the BMI chart is an unreliable method of determining if someone is really overweight. This is because BMI only calculates a height:weight ratio. It doesn’t take into consideration muscle and bone mass. In fact most bodybuilders are classified as dangerously obese. I really think it’s time to get a new method of calculating a healthy body weight.
Yeah, this is true on an individual basis. But, I think BMI are still valid for overall population trends. The percentage of people that BMI is inaccurate for is very, very small. I guaran-dang-tee you that the overall rise in BMI’s in the US is not due to millions of people suddenly taking up weightlifting.
We’ve been over this before, although it’s a little tough to find a link, as you can’t search for three-letter terms. The BMI is very cheap and quick to measure, and it does give some useful information: people with a high BMI are at a higher risk of death than they would be if their BMI were lower, even if their overall risk of death is lower than that of the general population.
As for the question in the OP, I seriously doubt it. No competent statistician would run the analysis without making corrections like that.
Does your cite mean that close to 70% of, the US population is overwieghted???
(33.6 overweighted+ 30.9 obese + 4.7 extremely obese)
Or did I miss something?
Yep. Click on the “source page”. It’s a compilation of statistics from the 1999-2000 National Health and Nutrition Examination Survey (NHANES).
There do appear to be some rounding or margin of error differences but the numbers are roughly right.
Unfortunately, we really do have a horrible problem here in the US (and it’s spreading to other Western countries as well) that’s gonna be a huge issue in the coming years.
Changing the BMI clearly made more people overweight. On the other hand, people have clearly become fatter since 1990 too. No doubt hundreds and thousands of people who have kept a stable body weight over the years did become overweight only due to the change in BMI. However, many more did not keep a stable weight during this time and would have had a bmi greater than 27 anyway.
No one thinks the BMI is a perfect tool, but the number of very muscular individuals who throw the curve off is pretty small. It is a reasonable standard for obesity due to the ease of calculation, but of course is far from the best possible standard or only measure.
Just as a relatively small percentage of overweight people have a genuine untreated thyroid disorder; only a relatively small percentage of people with high BMIs have it because of many years of bodybuilding.