There's also more and more rhetoric now about the microbial gut biome and the various stuff that we eat nowadays (antibiotics in meat, artificial sweeteners) changes whatever balance we might have had, once upon a time... you get the idea. The more I read, the more it seems like my "sometimes this makes me sick and sometimes it doesn't" experience with food, wheat in particular, is due to something more complicated. Possibly the sprue stage is a symptom rather than its own disease?
My partner has a similar condition (not celiac, not gluten sensitive, but 'something in bread' sensitive) and she found that sourdough from locally made starter was way easier on her system than anything from bakeries or the store.
(Source: We've been experimenting with breadmaking at home, so I've learned more than I ever expected to about bread over the past year.)
I don't have a strong opinion about the origin of the starter. It will definitely influence the flavor of the bread but other than that I don't think the origin is important. More important is the rise times. A longer rise is more likely to convert more sugars and also more likely to give indicators of a bad batch.
I said bakery, but there are commercial bakeries around and I meant a baker bakery (a boulangerie, if you will). The place I went to is the sort where you walk in, the bread is on wooden racks and they give it to you in a paper bag. I figured there are maybe three places I can think of that are more likely to be doing 'real' sourdough and they're all in the other direction.
I was watching that Michael Pollan series and he was talking about his theory that industrial bread was the problem and everyone would be fine if we went back to sourdough. Well this feels like one of those things that sounds good but has no substance, but clearly at this point I'm willing to try anything. There's a little bakery on my way home and they're open late. I've had half a loaf of sourdough bread in two and a half days and other than burping more, I feel no worse than I did last week.
What I wonder every time someone posts about ketosis is just how bad are sugars and starches for us, and how did we get this far without figuring it out?