PROBLEM TO BE SOLVED: To provide a method for reducing the glycemic index of a food product.SOLUTION: The method comprises the step of adding to the food product prior to consumption a dietary fiber composition in an amount of 2.5 g to 7.5 g of the composition per 50 g of available carbohydrate of a food product, effective to reduce the glycemic index of the food product by at least 5 glycemic index units, wherein the dietary fiber composition comprises from 48% to 90% (w/w) of glucomannan, 5% to 20% (w/w) of xanthan gum, and 5% to 30% (w/w) of alginate.【課題】食品の血糖上昇指数を低下させるための方法を提供すること。【解決手段】上記方法は、該食品の血糖上昇指数を、少なくとも５血糖上昇指数単位だけ低下させるのに有効な、該食品の有効炭水化物５０ｇ当たり食物繊維組成物２．５ｇ～７．５ｇの量の食物繊維組成物を、消費前に該食品に加える工程を包含し、該食物繊維組成物が、４８％～９０％（ｗ／ｗ）のグルコマンナン、５％～２０％（ｗ／ｗ）のキサンタンガム、および５％～３０％（ｗ／ｗ）のアルギナートを含む。【選択図】なし
