Because BMI isn't the strongest corelation.
We also investigated the relationship between obesity and the use of health care services including physician visits, hospital use, prescription drugs, home care, and personal care homes. This section, which capitalizes on the uniquely powerful health data system (the Repository) housed at MCHP, provides the most important contributions from this study. Overall, the results revealed that while the Obese group almost always had the highest rates of health service use, the differences between it and the Normal and Overweight groups were relatively small. That is, the health care system is not being overwhelmed by the demand for health services related to obesity. This finding is particularly important because no previous studies have been able to provide this kind of analysis on a large representative sample with such comprehensive data on health service use.
Furthermore, for a number of indicators, the higher rates were only evident for those at particularly high BMI values. For example, the Obese group had more physician visits per year than others, but only about 15% more overall...
Link and lots of interesting implications thanks to BigFatBlog.
Got that? High blood pressure is associated with being heavier, but heavier people do not have a higher prevalence of heart attacks. Could this be because of white coat syndrome or because many medical professionals measure fat people's blood pressure with cuffs that are too small? Or perhaps fat people naturally have slightly higher than normal blood pressure? All of those would result in higher brood pressure readings that wouldn't translate into a higher heart attack risk.
We've been seeing alarmist "studies" (and I use that term loosely) in recent years, purporting to show that fat people are going to bring down the world's health care systems with our high demand for services. Those papers are based on wild conjecture and statistical manipulation, but a lot of people take their claims for granted. Other papers have suggested that fat people have shorter life expectancies and will therefore use healthcare for fewer years, and that may cancel out our higher rate of health care use. Nobody, as far as I know, has challenged the idea that fat people use more health care resources than smaller people. Even I would have guessed that we use more resources on average, if only because of weight loss treatments. Weight loss treatments could certainly explain the 15% higher health care use by fat people in this report.
When the Flegal study revealed that people classified as overweight are at the peak of the life-expectancy bell curve, some people suggested this was because heavier people are being kept alive through the extensive use of advanced, modern medicine. This report makes that seem doubtful, as heavier Manitobans are not using significantly more healthcare resources than lighter ones.
The stress from stigma is likely to make some fat people sick
Second, to better tease these factors apart, I and a team of researchers sought to ascertain whether it was one's BMI or one's satisfaction with his or her weight that was most important in the relationship between adiposity and health. To do this, we used the 2003 Behavioral Risk Factor Surveillance System dataset, which contains a question asking subjects to place a numerical value on their desired body weight. In analyzing these data, we found that the difference between a subject's desired body weight and his or her actual body weight (a measure that captures the psychological dimensions of obesity) is a much more powerful predictor of morbidity than is BMI (a measure that captures the physiological dimensions of obesity).
Dieting increases vulnerability to stress:
Chilling out might be the key to losing the weight you gained over Thanksgiving. New research shows that dieting makes the brain more sensitive to stress and the rewards of high-fat, high-calorie treats. These brain changes last long after the diet is over and prod otherwise healthy individuals to binge eat under pressure.
Actually, it's a mouse study, and I haven't heard about it being replicated in humans. What's more, it buys into the premise that fat loss is really important, and we've gotta find a way to make it work.
Thinking about it and the above link, I wonder if dieting history is as much a factor in stress for people who are unhappy with their weight as social stigmatization is.
I haven't seen any studies that track dieting history and health. For that matter, I haven't heard of any studies which track the prevalence of various types of diet by duration and intensity. I realize such a study would be dependent on self-reports, but people seem to have rather vivid memories of their diets.
When I first ran into the idea of fat acceptance, I found myself resisting the idea, and I realized it was because I didn't want to believe that my home society was that much meaner than it thought it was. Then I remembered that I spent eight years in Hebrew school and those hours wouldn't be wasted if I remembered that the history of anti-Semitism was a clue that people just make up reasons to hurt each other, and there was no reason to think contemporary culture was immune.
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