Yep even old hats have bad days, literally right after I wrote this.
I was on the way home from vacation yesterday which despite a week and half on the road kept keot, I stopped at a small cafe half way. I ordered what appeared to be and after asking a few questions of the server, a ketoish friendly dish. A pork tenderloin roll, i asked the server what was in it and received the answer pork, spinach, broccoli and onions and cream. It was her second day and I probably should have known better when she had to go ask someone exactly what was in it.
After taking a few big bites and not really paying attention I got that distinct flavor, sweetness. It had corn starch sauce, no cream to speak of, there was carrots, no onions but had flavor of it, but some yam or sweet potato instead in a puree. In of itself it was very good, and I cannot complain about the dish or the server save the error about not saying what the sauce was. She apologized it was late at night and I needed to get moving.
So i have been keto since nov 1, I knocked myself out for thanksgiving and Christmas knowingly and once unknowingly over some gum/breath mints. I prepared for the times I knew, but at the time I was not fat adapted. The gum/breath mints was a minor amount and never really gave me issues other than just feeling off. I probably have over eaten protien a few times in there as well on vacation again no major issues other than feeling a little off.
I can say that I have never had a headache, or sinus pressure like that in my 44 years which hit a about 20 minutes later. Inside of an hour my joints were aching, and had more gas than I knew what to do with. I was home in 3 hours, and by then it mostly passed but so not worth it.