No matter what diet, you need a deficit. Nothing complicated.
Edit: I'm not signed up over there to read it, but I DO know for me, and a lot of people I've associated with, that while a calorie is a calorie, I'm totally on board with keto diets.. For me, it's a lot easier to set down black and white - Yes for this(FAT), No for that (CHO). I've dropped 6% in a month doing a keto so far, but not because of it being special, but because it leads to way higher energy for me. 6% really isn't anything special seeing as I started at 20% (FYI).