As
@Goonergal said, this is a "normal" reaction to being in Ketosis, not the dangerous Ketoacidosis. I am actually sad that I had breakfast networking which would knock me back today (I OMAD 4 to 5 times a week). I detailed this as an aid memoir, as I normally have much lower ketones due my love of nuts, so it was interesting to see a walk at two thirds of my normal distance, followed by short but focused heavy weights session gave optimum results for me (on this occasion, so will have to repeat a few times to be sure). I need to research if a number above 0.5 (recognised as nutritional Ketosis (some say from 0.3)) has extra benefit, it does correlate with low basal insulin.