Soybean flour has surged in popularity thanks to health-conscious consumers who are seeking a lower calorie alternative to standard flour without compromising too much on nutrition.

Since May, Mei Bao, a restaurant touting healthy Chinese food in Tokyo's Shimbashi district, started serving deep-fried noodles made from 100 percent soybean flour. The noodles have only 10 grams of sugar, about 75 percent less than those made from wheat flour.

"The dish is particularly popular among young women and male company employees who are conscious of their health," a restaurant worker said. "The noodles are almost sold out every day."