An object is to achieve a big effect about an agent for delaying digestion and absorption of lipid or a lipase inhibitor which is composed of specific triacylglycerol and fat-soluble and which exerts the effect more mildly with small used amount. An oil-in-water emulsion having 2 μm or less of average particle diameter, in which a melting point of a fat composition which composes an oil phase of the emulsion is 37° C. or less and the fat composition includes 30% by weight or more of BX2 triacylglycerol (B represents Behenic acid and X represents fatty acid having 4 to 24 carbon atoms) is simultaneously ingested with ingesting fat-containing food. An amount of the BX2 triacylglycerol with respect to fat amount derived from fat-containing food ingested simultaneously is preferably 0.5 to 20% by weight.
