I just plateaued on Keto. No weight loss for 3 weeks running yet since starting again in January its been a steady 1lb a week with no cheats at all. I had no idea you were supposed to do this. Im probably around 10% body fat currently though so im assuming its just one cheat meal not an entire day?
Ideally you'd want to carb load for a meal or maybe a day. And ideally you'd want to limit your fat intake when you carb load, because consuming fat and carbs together will result in fat storage from the insulin spikes. So something like sushi, or lots of rice with a chicken curry, or pasta with tomato sauce would be great.
Don't go too crazy with something like pizza. Have a slice or two on your cheat day, but don't overdo it, because your body will store a lot of fat.
The idea is to replenish your glycogen store and shock your system out of keto so that it stops adapting to your diet.
That being said, everyone's different. Plateaus can be hard to break through. Try different things and see if anything works for you.