Every 10-gram daily increase in soluble fiber reduced visceral fat (the dangerous kind) by almost 4%.
One of the great discoveries of modern science is that there are different kinds of body fat. Subcutaneous fat, the kind that's right under our skin, may not be lovable; but visceral fat, the kind that forms deep in the belly around our vital organs, is most dangerous to our overall health. After tracking population groups at high risk of visceral fat formation for five years, researchers at Wake Forest Medical Center have found a simple dietary way to fight this bad stuff.
The way to zero in and reduce visceral fat is simple: eat more soluble fiber from vegetables, fruit and beans, and engage in moderate activity.
[No fiber is digested, but soluble fiber forms a non-irritating gel when mixed with liquid in the stomach and prolongs stomach emptying time, allowing sugar to be absorbed more slowly.]
The study found that:
• For every 10-gram increase in soluble fiber eaten per day (e.g., 1/2 cup beans), visceral fat was reduced by 3.7% over five years.
• In addition, increased moderate activity resulted in a 7.4% decrease in the rate of visceral fat accumulation over the same time period.
“We know that a higher rate of visceral fat is associated with high blood pressure, diabetes and fatty liver disease,” said Kristen Hairston, MD, assistant professor of internal medicine at Wake Forest Baptist and lead researcher on the study.
“Our study found that making a few simple changes can have a big health impact,” Dr. Hairston says. Specifically:
• Ten grams of soluble fiber can be achieved by eating one-half cup of pinto beans, two small apples, or one cup of green peas;
• Moderate activity means exercising vigorously [e.g., brisk walking] for 30 minutes, two to four times a week.
In the longitudinal study, published in the June 16 online issue of the journal Obesity,(1) researchers examined whether lifestyle factors, such as diet and frequency of exercise, were associated with a five-year change in abdominal fat of African Americans and Hispanic Americans, populations at a disproportionally higher risk for developing high blood pressure and diabetes and accumulating visceral fat.
At the beginning of the study, which involved 1,114 people, the participants were given a physical exam, an extensive questionnaire on lifestyle issues, and a CT scan, the only accurate way to measure how much subcutaneous and visceral fat the participants had. Five years later, the exact same process was repeated.
Researchers found that increased soluble fiber intake was associated with a decreased rate of accumulated visceral fat, but not subcutaneous fat.
“There is mounting evidence that eating more soluble fiber and increasing exercise reduces visceral or belly fat, although we still don’t know how it works,” Dr. Hairston says.
“Although the fiber-obesity relationship has been extensively studied, the relationship between fiber and specific fat deposits has not. Our study is valuable because it provides specific information on how dietary fiber, especially soluble fiber, may affect weight accumulation through abdominal fat deposits.”
Next Trial – Fiber Supplements & Belly Fat
Hairston’s next study, expected to be in clinical trials later this summer, will examine whether increasing soluble fiber in the form of a common supplement (such as psyllium) will produce similar results to those obtained in this study using soluble fiber from food.
Funding for the study was provided by the National Institutes of Health.
Source: Wake Forest Baptist Medical Center news release, June 27, 2011
1. “Lifestyle factors and 5-year abdominal fat accumulation in a minority cohort: The IRAS Family Study,” Obesity, June 16, 2011.