On several threads I have suggested that people try Jerusalem Artichokes. They are prolific and take little care. This year I planted 6 tubers and got about 50 pounds to harvest. I have grown them in the past, but I have never taken them very seriously, this year I did some research.
Most of the tuber is inulin, which is a type of starch that the stomach cannot digest. This stuff does feed microbes in the small intestine and is therefore considered by many to be a healthy thing to eat. The advertisements for probiotics like in yogerts push them. Inulin can cause lots of gas however especially to folks who aren't used to it. Inulin also has beneficial attributes for diabetics. Bottom line is it looks to me that the plant could cause dijestive problems, and doesn't provide much in the way of calories. In other words a person could starve to death eating them.
Since I think that many of the folks who post here are interested in growing food because they worry about what the future may hold, I think that going down a Jerusalem artichoke rabbit trail may not be in our best interest. Sorry for the false lead. If you are still interested in Jerusalem artichokes there is a wealth of information if you google it.