Natto is short for Nattokinase. It’s a fermented soy bean that’s prevalent in Japan, and aids in digestion. Timothy Ferriss, author of The 4-Hour Chef, explains the health benefits of Nattokinase on the Dr. Oz show. He recommends eating 1-2 tablespoons first thing in the morning, and that by doing so not only will your digestion improved but also you energy level will increase.
You can buy Natto at many Japanese markets or make your own.