Fit's, a new gum on the market, is selling like hot cakes and beyond the expectations of manufacturer Lotte Co. and its rivals in the industry.

The key to its success is probably the weaker build of young generations, industry sources say. Young people don't like food with a tough texture and the new gum is softer than conventional varieties.

The fashionable, easy-to-open package as well as aggressive marketing via television commercials and YouTube have also boosted the sales of Fit's, which comes in three flavors: citrus, peppermint and mixed berry. In just four months, more than 30 million packs have been sold, Lotte said.