For me, if I’m deep in sugar land, I mentally prep for a day or so until I’m ready, then, over about 3 days I cut my consumption in half. Like, maybe the first day no actually candy or overtly the worst stuff. By day 4, I’m okay to go keto and have it all cut out.
When I cut it out, I went cold turkey and felt like death on Day 2. After a few weeks, I discovered that I actually feel like garbage after I eat something really sweet. I get a crazy surge and then crash hard. It helps me stay motivated to only indulge in the things that are really “worth it” - amazing birthday cake, Baked Alaska at a nice dinner, etc. Definitely learned not to break a fast with birthday cake or some other super sweet dessert. I try to eat some version of charcuterie an hour before the sugar, unless it’s a restaurant situation.