Wednesday, June 8, 2011

Thin Equals Well?

Many overweight and obese people are metabolically healthy, while large numbers of slim people have health problems typically associated with obesity, a new study shows.
The findings, based on national health data collected from 5,440 adults, shows that weight often is not a reliable barometer for health. In addition to looking at height and weight, the study, published this week in The Archives of Internal Medicine, tracked blood pressure, “good” cholesterol, triglycerides, blood sugar and an inflammatory marker called c-reactive protein, all of which are viewed as indicators of cardiovascular health.
Overall, thin people were still metabolically healthier than people who were overweight or obese. But being a normal weight was not a reliable indicator of health. In the study, about 24 percent of thin adults, or about 16 million people, posted unhealthy levels for at least two of the risk factors.
By comparison, among the overweight, about half the people had two or more of the risk factors. But half of them were also metabolically healthy. And nearly one out of three obese people were also metabolically fit.
While it’s long been known that it’s better to be fit and fat than being thin and sedentary, the new data are believed to be the first time researchers have documented the unreliability of body size as an indicator for overall health.

This is another report documenting the "fat but healthy" population, which has been reported on in various studies for at least five years.  The challenge is that with epidemiological studies - the assumption define the results.  If you decide that people with blue warts are more likely to die, aka blue warts are a risk factor, then fat people with blue warts are not "healthy".  Does that mean they are really more likely to die?  Who knows  - because most of the "risk factors" are the results of sophisticated calculations that are very rarely confirmed via intervention studies.  That said, Mike Eades ( published a post recently that explains how the "skinny fat/unhealthy" idea could very well be true.

The basic idea is that we each become insulin resistant on a different genetic template.  Suppose a person's fat cells are the last part to become insulin resistant - if they are eating poorly, they can continue to sock away excess blood sugar in their fat cells (after conversion, by the action of insulin, to fat).  In fact, these folks can and will accumulate more fat than the rest of us, and it seems to have almost a protective effect - because they can continue to sequester excess blood sugar long after many of us would not be able to.

On the other end of the spectrum, imagine a person who's fat cells become insulin resistant at essentially the same time as other tissues - these folks will not be able to buffer their excess blood sugars, and will wind up with a large quantity of visceral fat, which is "associated" with higher mortality.  They will suffer more damage from their overconsumption of carbs and the resulting high blood glucose.

What's the bottom line?  There's no getting around the fact that a large abdomen and high blood sugars are signals of damage and causes of damage respectively.  This is why carb restriction is such a powerful tool for those already wrestling with the damage the results from too many years of a typical neolithic diet.

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