Junkfood Science: When does it stop becoming a paradox?

June 19, 2007

When does it stop becoming a paradox?

As has been shown in heart failure and kidney failure patients, this study found that obesity was associated with a lower all-cause mortality risk for people without heart failure. It was reported in the news as another “obesity paradox,” along with attempts to explain away the findings and give repeated admonitions that this doesn’t really mean obesity offers a health advantage.

This study with more good news about fat is being reported here because it’s one that hasn’t yet been mentioned in our Obesity Paradox series. Yes, it’s another one. The news reported:

“Obesity paradox” seen in range of heart ills

Among men with symptoms of heart disease, those who are obese tend to live longer than their normal-weight counterparts, a new study suggests. Researchers found that among nearly 6,900 male veterans assessed for symptoms of heart disease, those who were obese were less likely to die over the next 7.5 years compared with normal-weight men. Past research has linked obesity to longer survival among people with heart failure, a chronic condition in which the heart muscle is too weak to pump enough blood to meet the body's needs. Some studies also suggest that obese patients fare better following heart bypass surgery.

Now the new findings, published in The American Journal of Medicine, suggest that this so-called "obesity paradox" extends to other heart disease patients as well.

The study does not, however, mean that obesity is a health boon... A lifetime of obesity might have different effects on longevity, they speculate.... Because the study group consisted of older men with heart disease symptoms, the findings may not be broadly relevant, McAuley and his colleagues point out. It's not known, for example, whether in a group of initially healthy people, obese individuals would tend to live longer.

More studies, the researchers conclude, are needed to fully understand the reasons for the obesity paradox.

Junkfood Science readers no doubt caught the inconsistencies in the attempts to create uncertainty surrounding this study’s findings. We know that the body of evidence, as even acknowledged by an expert review conducted by the National Institutes of Health, shows that weight gain with age or stable weights even if fat, for both men and women has the lowest death rates; while dieting, weight loss or fluctuating weights (yo-yoing), significantly increases the risk of actual death, cardiovascular diseases, type 2 diabetes and cancers.

And since few young people die of heart attacks —the biggest cause of death as we age — examining deaths among the highest risk population of older people with possible heart disease symptoms would be logical.

Yet, the article actually suggests that being healthier might be deadlier?

Questioning if the finding would be seen among a group of “initially healthy people” were negated in the study’s findings. The researchers made a specific point of explaining that they chose to study former veterans (most vets in this study were men) because they had had to meet rigid military fitness requirements and were initially as healthy as they come. Heart disease is a disease of aging, and even fit veterans were not immune.

These researchers put the study population through an extensive physical examination to identify health problems and they tested their cardiorespiratory fitness by maximal exercise testing. They excluded underweight people from their analysis, as this demographic is known to have the highest mortalities, and to eliminate possibly undetected medical conditions. Even among the overweight and obese people, there were more fit ones than unfit, although compared to the normal weight people, fewer overweight and obese were at “high fitness” levels (39% -38% - 24%, respectively). Still, even without adjusting for fitness levels in this study, obesity was associated with a 22% lower mortality risk as compared with being normal weight.

The fat people also had higher incidences of high cholesterol, hypertension and diabetes. But these factors proved to have surprisingly less impact that might be expected, with age and gender proving slightly more predictive of mortality than did all of the cardiac risk factors and history of heart disease, heart attacks and stroke combined.

During the average 7 1/2 years of followup, the researchers reported: “Death occurred in 31% of the normal weight group, 22% of the overweight group, and 18% of the obese group....we found that mortality was lower in veteran patients with higher BMI.” Adjusting for fitness, they found obesity was associated with a 35% lower mortality and that “each 1-unit increase in BMI conferred a 3% survival benefit.”

Their finding of an obesity paradox concur with other findings, they said. Of course, this study's findings are reported in terms of relative risk, rather than absolute numbers -- not unlike many studies being used to scare us today. To get a better picture of what actual numbers look like, they shared these graphics from the Aerobics Center Longitudinal study of over 25,000 men followed for more than ten years. [I know they're difficult to see, but they show that age is the biggest risk factor for death. The older we get, the fewer of us are around, no matter what size we are. We're more alike than anything. Like most studies, there's a small, consistent survival advantage the heavier we are. The main point here is to see that being fat isn't the death sentence that we're being led to believe it is.]

With health benefits associated with fat, can it continue to be called a disease? There are "health risks" associated with people of all shapes and sizes, so pointing to those among a certain group of people doesn’t make them a disease. Thin people get the very same diseases as fat people do and everyone has their own issues. We’re all human and more alike than not.

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