Faced with tightening competition for the textiles it's been making for almost 100 years, Omikenshi Co. is trying to get into the health-food business, using its cloth-making technology to turn trees into noodles.

The Osaka-based company's best-selling product is rayon, a fiber made from tree pulp. Using a similar process, Omikenshi is turning the indigestible cellulose into a pulp that's mixed with konnyaku (devil's tongue), a yam-like plant grown in Japan. The resulting fiber-rich flour, which the company calls "cell-eat," contains no gluten, fat and almost no carbohydrates. It has just 60 calories a kilogram (27 calories a pound), compared with 3,680 for wheat.

Omikenshi is betting on a health food market worth ¥1.2 trillion in 2013, more than double the level two decades earlier, according to the Consumer Affairs Agency.