Being Slightly Overweight May Lead To Longer Life 383
Hugh Pickens writes "Findings of a new study show that underweight people and those who are extremely obese die earlier than people of normal weight — but those who are only a little overweight actually live longer than people of normal weight. 'It's not surprising that extreme underweight and extreme obesity increase the risk of dying, but it is surprising that carrying a little extra weight may give people a longevity advantage,' said one of the coauthors of the study. 'It may be that a few extra pounds actually protect older people as their health declines, but that doesn't mean that people in the normal weight range should try to put on a few pounds.' The study examined the relationship between body mass index and death among 11,326 adults in Canada over a 12-year period. The study showed that underweight people were 70 percent more likely than people of normal weight to die, and extremely obese people were 36 percent more likely to die. But overweight individuals defined as a body mass index of 25 to 29.9 were 17 percent less likely to die than people of a normal weight defined as a BMI of 18.5 to 24.9. The relative risk for obese people was nearly the same as for people of normal weight. The authors controlled for factors such as age, sex, physical activity, and smoking. 'Overweight may not be the problem we thought it was,' said Dr. David H. Feeny, a senior investigator at Kaiser Permanente Center for Health Research. 'Overweight was protective.'"
Re:BMI Is not a Good Measure (Score:5, Informative)
Agreed. I was 10 pounds over my "ideal range" five years ago. But I was lean and had decent upper body muscle from doing a lot of construction work. After ending that, I made a conscious choice to drop those ten pounds since I knew I would not be keeping the muscle. So, I became "ideal weight" even though I was in worse shape physically. Since then I have put on those 10 pounds (mid-age metabolism slow down). So according to the chart, I am in the same place I was five years ago.
BMI is a nice quick rule-of-thumb, but the better test is to see how long it takes for you to get winded running at a moderate pace.
(and thanks Slashdot for the five minute wait between posts)
Re:Okay, noob question time (Score:2, Informative)
There is no ideal weight range, only idea percentage of body fat.
Re:Muscle Weighs more than Fat (Score:3, Informative)
I'm not going to say BMI is a horrible thing, but as a critical data point in a study like this it is far too inaccurate. Body fat percentage seems like a much better factor.
Re:more likely to die! (Score:3, Informative)
That kind of survival statistic is always measured within some specified period of time, usually a year for this kind of study. So if, say, the annual death rate is 100 per 10,000 for people of normal weight (just pulling the number off the top of my head here), 170 per 10,000 for underweight people, and 136 per 10,000 for obese people, then the statement is correct.
Re:BMI Is not a Good Measure (Score:3, Informative)
Aside from the fact that even the summary says the study correct for physical activity, BMI is just weight normalized among height/gender. It may not be as good as body fat %, but its a load better then just weight. That said, BMI is still a good measure of the fat for the population. Your average person does a light amount of exercise. I'd say, the very active people are outmatched by the sedentary people. Given BMI accounts for the average, the sedentary people, who have a high fat:muscle ratio compared to a normal person, probably make up for the very active people who have a high muscle:fat ratio. In other words, for every guy who has 5 lbs more muscle then a normal guy of the same weight, there is probably a guy who has 5 lbs less muscle then a guy of normal weight. It's also a hella lot harder to put muscle on then take it off...
Re:BMI is a bad measure. (Score:4, Informative)
There's a big problem with the BMI. It's a quadratic aproximation to a cubic mesure. I.e. the body should be proportional to the cube of the height.
No, it most certainly shouldn't.
Cube square law.
Large humans cannot be scale models of small humans. Bone strength is proportional to the square of the linear dimension, not the cube. If you scale the skeleton up by a factor of X, the mass you hang on it had better scale up by no more than X^2. Check out Haldane's essay "On Being the Right Size [ucla.edu]"
Re:Okay, noob question time (Score:3, Informative)
Alternatively, one could simply drink a glass or 2 of water, and rid themselves of the excess salt.
Kidneys are amazing things. It takes a hell of a lot of salt, or a very bad case of dehydration, to keep them from regulating your body's salt content.
Re:BMI Is not a Good Measure (Score:3, Informative)
except it proved the opposite. Being ripped and overweight with muscle makes you live longer.
That's just the problem--it didn't show anything about being extremely "heavy" and having a low BF%. You are conjecturing that such people skewed the results. The study controlled for activity level, so I'm not sure that skewing occurred. (The least skewed part of the results should be the part that applies to inactive people, because body builders will not be part of this group.)
Re:They're asking the wrong questions, as usual. (Score:4, Informative)
http://usgovinfo.about.com/od/healthcare/a/tallbutfat.htm [about.com]
Re:Did they control for sickness? Alcohol studies. (Score:2, Informative)