A method for reducing blood glucose level increase is provided that includes: providing a reducer of blood glucose level increase, wherein the reducer comprises isomaltulose; having an individual ingest the reducer; and having the individual consume a carbohydrate having an α-1,6-glucosyl bond ratio of from 0% to less than 50% relative to the total bonds among constituent saccharides, wherein the reducer is ingested before or after or simultaneously with consuming the carbohydrate, and wherein the reducer reduces an increase in the individual's blood glucose level caused by consuming the carbohydrate. The reducer of blood glucose level increase includes isomaltulose (PALATINOSE™) as an active ingredient so that when the reducer is ingested and a carbohydrate having an α-1,6-glucosyl bond ratio of from 0% to less than 50% relative to the total bonds among constituent saccharides is consumed, an increase in blood glucose level caused by ingesting the carbohydrate is reduced.