Soybeans have been cultivated in Asia for hundreds of years and produce more protein per acre than any meat or other vegetable crop. This is an important source of protein when you have the large populations as in China or the limited land space, as in Japan. Soybeans are high in both protein and vitamins and minerals. Look at the variety of products from soy: Soy milk, textured soy protein, edamame (edible green soybeans), tofu, cooked yellow soybeans, soy oil, and many more. This one plant could very well be responsible for how two Asian cultures thrived.