Wouldn't do anything for me as I said my metabolism doesn't really slow down much when I do a contest diet. I've heard a lot of talk about metabolism slowing down but have yet to experience it or talk to people who have. If your metabolism slows down I think it's because you went too low in calories and you will have to restart it by eating more of this I have no doubt. As a planned part of your diet, I would say a big no, why plan to screw up. Don't drop cals too low too soon and you should be ok.
CKD is different you need to restore glycogen. Why you would have to take in so many cals like perscribed on most CKD diets I have no idea, it defies common sense and I'm doing fine keeping my cals just below maintenance on my refeed days. I guess it depends on how effecient your body is. Mine sucks those carbs up like a sponge.