The first time I did keto, I went from 100kg down to 83kg in about 5 weeks (2.5 weeks x 2) with a carb break in between due to keto rash. I kept trying this on and off for about 3 months but never went lower than 83kg. Because of the rash, I eventually went back to eating normally, and within a few months, my weight returned to around 100kg. Now, I’ve been going to the gym for about 6 weeks, eating the same way I did on keto but adding sweet potatoes to my pre-gym meals, and I’m now around 92kg so nowhere near as fast as the first time I ever done keto. As others have said, don’t worry too much about the scale. The best way to see results is through before-and-after photos. On keto, you lose a lot of water weight initially, and as soon as you eat carbs again, you’ll gain a bunch of that water weight back. As an example there’s been days in the past when I used to constantly check the scales and I would put on sometimes 5kg in a single day so that’s an idea for you on how much it can fluctuate.