RE: Food for thought: The common household ingredient that scientists claim is WORSE for you than sugar.
It wasn't a big part of their diet a few thousand years ago. More like a spice than an actually food it might of even been grown as fertilizer for actual food crops.
Native to north-east China (Manchuria), the soybean (Glycine max) was cultivated some 3,000 years ago, The plant’s wild precursor was a recumbent vine, G. max var. ussuriensis. During the early centuries of domestication, the soybean was nothing like as important in the Chinese diet as it is today. In fact it may well have been far more useful as a fertiliser than as a food - ploughed back into the soil to enriching it for other crops such as wheat or millet. The soy plant is fortunate to be a member of a family of plants that has the ability to draw nitrogen from the air impart it into the soil through its roots thus enriching poor soils. Soybean plants may also have been rotated with other crops, for this same purpose.
Did you only read that paragraph? That was 3000 years ago. It took time but they shaped it into a nutritious and healthy bean. And have been eating it for at least a thousand years. Japan 1500 years.