Well try it and see how you go, but I think you will find it much harder to stick too, and your metabolism will bottom out after 3 days. Once its bottomed out, you maybe in a catabolic state depending on how low your calories are, nothing short of a week long pig out will restore it, best to not get there in the first place.
I'm just basing it on my own experience though.
Its up to you, but I eat everything I want. Yesterday was my pigout day - here is what I ate
meal 1 - 2xweetbix + soy milk, small chicken breast and veges
Meal 2 - Microwave popcorn has 22grams of fat
Meal 3 - some Japanese pea chip junk food
meal 4 - 2 packets of chinese instant noodles, with 2 eggs cracked into it, with onions and lettuce added.
meal 5 - 4xWeetbix with margarine spread on em
meal 6 - Pizza Hutt pizza - ate a lot of it!
I dunno how many cals are there, but must be quite a bit
You just gotta let go of your fear to eat! Even if you gain a bit of fat its all good, because your still ending up leaner over the long term without slowing down your metabolism into rebound territory. Like I have said before zig-zag you calories and your bodyfat percentage.