The New York Times today has an article about obesity, showcasing new studies that find weight isn’t that important as an indicator of health:
Despite concerns about an obesity epidemic, there is growing evidence that our obsession about weight as a primary measure of health may be misguided.
Last week a report in The Archives of Internal Medicine compared weight and cardiovascular risk factors among a representative sample of more than 5,400 adults. The data suggest that half of overweight people and one-third of obese people are “metabolically healthy.” That means that despite their excess pounds, many overweight and obese adults have healthy levels of “good” cholesterol, blood pressure, blood glucose and other risks for heart disease.
At the same time, about one out of four slim people — those who fall into the “healthy” weight range — actually have at least two cardiovascular risk factors typically associated with obesity, the study showed.
They go on to say that the factor most strongly correlated with overall health is not the ever-popular Body Mass Index, but rather fitness:
Those with the lowest level of fitness, as measured on treadmill tests, were four times as likely to die during the 12-year study than those with the highest level of fitness. Even those who had just a minimal level of fitness had half the risk of dying compared with those who were least fit.
This will not come as a surprise to anyone who has ever put the stats for their favorite pro athlete into a BMI calculator (you want to tell Michael Strahan he’s obese?), but it’s nice to see it holds more widely.
As someone who’s “overweight” according to BMI but runs about 35 miles per week, that’s extremely heartening news!
I agree. I’m 5’9″, and my healthy weight could go all the way down to 128 pounds according to the Department of Health BMI chart. I think I’d look pretty scary at 128 pounds.
The BMI is utterly without foundation.
The Metropolitan Life Insurance Company began putting height and weight on their applications for life insurance, hoping to build a predictive model of life expectancy from those figures. The figures were accepted at face value and never verified, so it’s understandable that people inched up their heights and pounded down their weights. Also, the values were never updated through the life of the policy. Since most couples got life insurance before their first pregnancy, the initial figures would no doubt be invalid by middle age.
The first model was strictly linear. For a man of a given height, weight should be so many pounds, and add this many pounds for each additional inch. A similar model was developed for women.
The linear model was a complete disaster as a predictive model of longevity, and was abandoned by Metropolitan.
Subsequently, some people tried developing a quadratic model, where weight should be proportional to the square of the height. This was simply a guess, a hope that it would work better than a linear model. However, since it is utterly without scientific foundation, it is just plain stupid.
The BMI ignores all the scaling laws discovered in serious work in physiology and biology, and it ignores what we know about animals in nature. If you look at the cutoff lines, they are obviously arbitrary, being nice round numbers. Ask yourselves how those numbers would be verified by experiment.
Testing is the beginning of the end. When this nonsense is put to tests, it comes apart quickly.
Parker-Pope has been gradually coming to this realization, and I hope that my comment on a related post of hers last week (link at my name) might have spurred her on to continue to explore this.
Fitness and the ability of people to engage in essential activities of daily living, their work/school/social role activities and in their preferred and appropriate recreational and social activities is a better overall indicator of fitness when evaluated in concert with multiple physiological indicators. Body weight is only one indirect indicator which has been fully exploited by many industries to spur people to buy fashion, make-up, body enhancement products, and weight-related foods, supplements, hardware, software and services, etc. ad nauseum.
The more we can move away from the artificial and oft damaging notion of weight equating with health as a sole indicator, the better we’ll be to address more critical factors: acquiring and eating nutritious foods, engaging in more and sustained activities, attending to the needs for clean water, food and air, and translating these into policy for community development and sustainability.
Normal middle-aged systolic blood pressure was Officially 140 torr for decades. It was reduced to 130 torr and now 120 torr is “recommended”. 120 torr would put about 80% of people 45 and older on hypertension meds. Merchandizing!
http://www.ncbi.nlm.nih.gov/pubmed/18166406
“Cost-effectiveness of treating ocular hypertension”
Allowing ocular hypertension to untreated progress into glaucoma and partial vision loss will save a healthcare provider more than $45,000/patient.
Follow the money.
I’m having one of those “well duh” moments at this story.
Still, I love your suggestion of putting the pro-athlete into BMI. Phelps is 22.0. I am 22.0. Does this mean I’m as healthy as Phelps?
I wish it meant I could eat 12,000 calories a day (as he supposedly does)!
CRM-114
The BMI is older than you think:
http://www.straightdope.com/columns/080229.html