Summary: Dietary fat containing 5% sucrose polybehenate, a non-absorbable food additive, is fed in a semi-synthetic diet containing absorbable fat to rodents. The animals eat the diet ad lib for 3 days. Two or more fecal pellets are collected on days 3 and 4. Fat absorption is calculated from the ratios of behenic acid to other fatty acids in the diet and in the feces as analyzed by gas chromatography of fatty acid methyl esters.