For me, it stopped when I knew I was "fat-adapted." Craving for between-meal snacks stopped. Desserts sort of lost their appeal aside from very occasionally... So, yeah. It won't last forever as long as you can stick with it.
But... As for how long... Sorry man, can't tell you. Everyone has a different metabolism, different nutritional needs, etc. this will, without a doubt, mean that everyone will take a different amount of time to fully adjust. Some people will do it over a few days, some people in a month, others will take several months. It all just takes time. Just breathe deep and hang in there! It'll get better at SOME point.
"The cling and a clang is the metal in my head when I walk. I hear a sort of, this tinging noise - cling clang. The cling clang. So many things happen while walking. The metal in my head clangs and clings as I walk - freaks my balance out. So the natural thought is just clogged up. Totally clogged up. So we need to unplug these dams, and make the the natural flow... It sort of freaks me out. We need to unplug the dams. You cannot stop the natural flow of thought with a cling and a clang..."