dugdeep said:
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I don't know if something I've been eating specifically has been aggravating it (I suspect onions) or if it's just the carbs in general that my body isn't handling well. It could be that my digestive tract no longer has the ecology to handle fiber at all. I've started taking a probiotic and am going to be trying my hand at Megan's experiment with the sauerkraut to try and establish a better bacterial environment.
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I didn't make a point of it and perhaps I should have, but this always applies: introduce the new foods one at a time, some days apart. I started with chard, I think (already thoroughly tested), then sauerkraut, followed some days later by mushrooms, followed some days later by onion. If you have reason to think a particular food could be trouble, give it even more time.
The only veggie I was concerned about was onion, because it has a higher density of carbs. When I say onion, by the way, I mean a thin slice of onion, not a whole onion. I have been going through less than one whole onion per week. That way the net carbs are only about 1 g/d.
The chard, sauerkraut, onion, and mushrooms add up to around 3-5 net carbs a day (depending on what I have), which may not really even "count" as I described earlier.
I checked my late-day ketones before and after starting this and they were at 2.4 mMol/L both times, with fasting glucose around 90. It would help if others trying the fermentables would check their ketones & glucose too to see what, if anything, happens.