I am having trouble as well. Not sure why, but the switch to lower protein has set off afternoon cravings. The odd thing is that breakfast is essentially the same as before, as well as lunch, it is just that I have less protein for dinner, which should not effect my afternoon. Unless it is about the idea of feeling deprived? I dunno.
For now, I am not going to worry about it. I am going to continue to keep the carbs low and go back to trying to keep each meal with less than 25g of protein instead of 20g. Hopefully that will take care of things.
p.s. I googled "blood ketone monitor" and decided to go with this site Nova Max Ketone Strips With FREE Glucose & Ketone Meter Kit | Glucose Meter I am sure you can get them at any drugstore, just make sure you get one that tests blood ketones and the sticks that will do the same.