I haven’t read a good explanation of the Whoosh effect, but they are real! I had lost a significant amount of weight over a 12 month period. Then I seemed to hit a wall. After a 3 month period with no significant change, I stopped weighing regularly just to avoid the inevitable frustration. I weighed this morning for the first time since July 12. Over a month (and a trip to Ketofest).
Down 16 pounds! Whoosh!
It’s only ever happened to me once, but it’s a real phenomenon. I didn’t believe it at first, because it was so weird to suddenly be weighing so many pounds less.
I would not want others to think that is normal and get discouraged if they don’t see losses of that magnitude. That was over a six week period that was following a 3 month period of no loss. So averaged out it was probably around a pound a week. It just showed up on the $#@ scale at one time. Also, I am still very overweight and more rapid weight loss seems to be easier the more fat you have to lose.
That’s the part that gets me. You have no clue it’s coming, and then when it happens it seems so fucking arbitrary! 
This explains the whoosh - http://100down.org/the-whoosh-effect/
