To provide an oil and fat composition that is highly safe and effective for the prevention or treatment of diabetes that does not cause side effects even when continuously taken. The fat or oil composition for preventing or treating diabetes according to the present invention contains triacylglycerol as an active ingredient, and the triacylglycerol has one or two medium-chain fatty acid residues in the molecule, and is composed. The fatty acid contains a medium chain fatty acid having 6 to 10 carbon atoms and a long chain fatty acid having 16 to 24 carbon atoms.安全性が高く、継続的に摂取しても副作用の懸念がない、糖尿病の予防又は治療に有効な油脂組成物を提供すること。本発明の糖尿病の予防又は治療用油脂組成物は、トリアシルグリセロールを有効成分として含有し、当該トリアシルグリセロールは、分子内に中鎖脂肪酸残基を１つ又は２つ有し、且つ、構成脂肪酸として、炭素数６～１０の中鎖脂肪酸と、炭素数１６～２４の長鎖脂肪酸とを含有することを特徴とする。
