I know quite a few folks here are interested in traditional foodways, so I thought I would turn to you all with this question.
Modern Chinese cuisine is full of vegetable oils, wheat flour (in soy sauce, sauces, and people are eating way more breads), and, increasingly, sugar.
We know all of these things were either very rare or completely unavailable until fairly recently, but I want to know more details. Such as:
What were the most common staple foods before white rice became so cheap? Here in southeastern China I suspect taro and other root veggies.
Were the original soy sauce and rice wine wheat-free? I'm almost certain they were, but I have no real evidence to point to other than that white flower was clearly a luxury item until recently.
When did rapeseed oil become common? This is considered the "traditional" oil by many here, because it's what older folks often use. But I suspect this is also a fairly recent introduction. I'm sure lard was much more common, and I'm guessing there was more stewing, steaming, boiling, etc.
Has tofu always been as common as it is now? I suspect no, as extracting soy milk and processing it would have been quite labor-intensive.