Soluble fiber decreases belly fat

It's well known that visceral fat (visceral adipose tissue, VAT—the fat in the abdomen that surrounds vital organs) is associated with chronic inflammation, metabolic syndrome, diabetes, fatty liver disease, hypertension and other mounting ailments. Research published recently in the journal Obesity offers welcome evidence that consuming soluble fiber significantly decreases VAT. As the authors did, the most accurate way to determine the amount of VAT is with CT scans...

"The objective of this study was to examine whether lifestyle factors were associated with 5-year change in abdominal fat measured by computed tomography (CT) in the Insulin Resistance and Atherosclerosis (IRAS) Family Study."

They measured visceral (VAT) and subcutaneous (SAT) adipose tissue at the L4/L5 vertebral level at baseline and at 5 years for 339 subjects ages 18-81. Examining physical activity and dietary intake, they assessed the associations between change in fat accumulation and a number of relevant variables including physical activity and soluble and insoluble fiber intake. Their data showed benefits for both physical activity (no surprise there) and soluble fiber:

"Soluble fiber intake and participation in vigorous activity were inversely related to change in VAT, independent of change in BMI. For each 10 g increase in soluble fiber, rate of VAT accumulation decreased by 3.7%. Soluble fiber was not associated with change in SAT. Moderately active participants had a 7.4% decrease in rate of VAT accumulation and a 3.6% decrease in rate of SAT accumulation versus less active participants. Total energy expenditure was also inversely associated with accumulation of VAT."

Ten grams of soluble fiber is approximately equivalent to a cup of green peas, two small apples and a half cup of pinto beans. (See also an earlier post on prunes.) The authors conclude:

"Soluble fiber intake and increased physical activity were related to decreased VAT accumulation over 5 years."