Your brain needs lots of energy to function. It needs EXTRA energy with PCS. Healing takes energy, which takes calories, which requires healthy foods. The new neuro path ways formed after injury/healing are not as efficient, and so still require more energy/glucose than normal.

I'd strongly suggest against such a cleanse. I think a cleanse with lots of whole veggie and fruit juices, some lean proteins and carbs would be good. I find I can't go more than 2-3 hours with out eating - and a veg/fruit juice (not with sugar, but a whole, fresh juice) really helps.

Good luck!