No, not exactly, however your BMRs will adjust in relation with your new weight so if you don't adjust your intake then you will regain and/or plateau. Many folks don't realize this fact which contributes to weight gain when exercise stops and diet isn't properly adjusted..
I am one of 8% who cannot, absolutely cannot "shut up the cake-hole". But I will not be able to survive on coconut butter and meat for 6 weeks either. 10 hours is my personal best on pure fat. Obviously, every morning I am determined to do whatever it takes to lose fat, but by mid-afternoon it turns out that i am not capable. Not to mention organic lamb is not exactly universally available. In fact I was advised we have a shortage here, in Alberta, and I am on the waiting list for lamb for the next year.