Carbs after keto

Indeed. I worked in an office where virtually everyone went low-carb at the same time like some sort of madness-of-crowds craze. Most of them lost a ton of weight fast, like 15 lbs in a month, and then gained much of it back as soon as they stopped doing low-carb a month or two later, which bummed everyone out hugely.

At the time, I didn't understand the carb-water retention thing, nor did anyone else in the office, so a kind of superstitious "cargo cult" mentality set in, wherein folks would go back to low-carb to curtail the weight gain and, voila, the weight would drop off again. Unfortunately, the cargo cult mindset, in which the Gods repeatedly prove that they really do favor you if you just do what the priests tell you to do, does apply to low carb diets. You WILL lose scale weight fast if you cut carbs, and you WILL gain scale weight back if you go back to carbs, but it's just water rebalancing, as @mmapags explains above. Since very, very, very, VERY few people will remain low-carb forever, due to the fact that carby food is great, that water rebalancing and scale increase is going to take place sooner or later, and therefore the artificially low scale numbers achieved on a low carb diet are best seen as temporary.

https://en.wikipedia.org/wiki/Cargo_cult