MONDAY, August 11, 2008 (Health.com) — Is it possible to be fat and healthy? Two major new studies published this week in Archives of Internal Medicine suggest the answer is “maybe,” depending on where the fat lurks in your body. In normal and overweight people, those with belly fat are at greater risk of heart disease and diabetes than those with extra padding in the buttocks or thighs.
But for the obese, the ultra-high-risk spot may be fat accumulation in the liver.
Not all excess fat is created equal
In one study, researchers at the University of Tübingen, Germany, divided 314 patients into four groups: normal weight, overweight, obese but still sensitive to insulin, and obese with insulin resistance. They found that not all the obese patients had the same health profiles. Some had clogged arteries, which is a heart attack risk factor, and were insulin-resistant, a precursor to diabetes in which the body loses its sensitivity to the blood-sugar-regulating hormone.
But about 25% of the obese people had clear arteries and no insulin resistance—indeed, these people looked no different than normal-weight participant in those terms.
“No one would say overweight is healthy,” says Lewis Landsberg, MD, of the Northwestern University Comprehensive Center on Obesity in Chicago. “The message is that being overweight is much more unhealthy for some people than others.”
How humans are like force-fed geese
The big difference between obese patients and their healthier peers seemed to be the percentage of fat in the liver. Obese people who were insulin-resistant more than roughly double the amount of fat in their liver as obese people who were not (8.8% vs. 3.5%, respectively).
In comparison, normal weight and overweight people had a liver-fat level of about 1.9% and 3.8%, respectively.