I'm surprised 16 hours was enough. Don't want to knock your diet, whatever works works, but when I did keto and one meal a day I was measuring my being in ketosis with the urinalysis strips. It used to make me a good 2 - 3 weeks of near zero carbs to get into ketosis and if I had a full carb meal like pasta or pizza it would take me as long as 2-3 days to dip back into ketosis. That said, I wasn't working out as much as I could have been so that could make the difference. #broscience