Even slim people can have internal fat collected inside or around the liver, gut, heart and pancreas, or streaked through under-used muscles.
Images from MRI scanners suggest that up to four out of 10 people could be a “Tofi” — thin outside, fat inside.
Professor Jimmy Bell, head of the molecular imaging group at the Medical Research Council’s centre at Imperial College, London, said this hidden fat could trigger heart conditions and diabetes.
The findings are raising questions about the BMI (Body Mass Index), the indicator of obesity used by doctors and public health campaigners.
The BMI is a relatively crude measure which takes into account a person’s height and weight. Some doctors believe the BMI is flawed because it pays no attention to the nature of the weight. story at the Telegraph UK
Deposits of fat (ectopic fat) in a lean body such as in the liver, muscle, heart, pancreas and kidneys may shed light on the development of insulin resistance and type-2 diabetes. A short abstract is online at the International Journal of Body Composition Research.
MSNBC reports an AP story:
According to Professor Bell, people who are fat on the inside are essentially on the threshold of being obese. They eat too many fatty, sugary foods — and exercise too little to work it off — but they are not eating enough to actually be fat.
“If you just want to look thin, then maybe dieting is enough,” Bell said. “But if you want to actually be healthy, then exercise has to be an important component of your lifestyle.”
Early warning of deep belly fat
Measuring levels of a chemical found in blood offers the best indicator yet of the amount of fat surrounding abdominal organs, according to a new study of lean and obese individuals reported in the July issue of Cell Metabolism, a publication of Cell Press. The buildup of such “visceral fat” is of particular health concern as it has been linked to insulin resistance, type 2 diabetes, and heart disease risk.
The researchers, including Barbara Kahn and Timothy Graham of Harvard Medical School and Matthias Blüher of the University of Leipzig in Germany, showed that “retinol-binding protein 4” (RBP4) is produced in much greater amounts by visceral fat compared to the subcutaneous fat that lies just beneath the skin. Moreover, they report that blood serum levels of RBP4 jump in people who are obese, who have double or even triple the concentrations found in individuals of normal weight.
“We believe that in the near future, measurements of RBP4 serum concentrations might serve as a novel biomarker for visceral obesity and increased risk for type 2 diabetes and other adverse outcomes of visceral obesity.” [story]
The U.S. obesity prevalence increased from 13 percent to 32 percent between the 1960s and 2004, according to researchers at the Johns Hopkins Bloomberg School of Public Health Center for Human Nutrition.
The prevalence of obesity and overweight has increased at an average rate of 0.3–0.8 percentage points across different sociodemographic groups over the past three decades. Some minority and low socioeconomic status groups—such as non-Hispanic black women and children, Mexican-American women and children, low socioeconomic status black men and white women and children, Native Americans and Pacific Islanders—are disproportionately affected. The meta-analysis was published online on May 17, 2007, in advance of the 2007 issue of the journal Epidemiologic Reviews. [story]