I've had a acrid taste in my mouth for a couple of days and wondered what it could be since the diet has been pretty consistent with the occasional deviation (The occasional diet soda is still a challenge to be overcome). It has been suggested that the acrid taste may be heavy metals purging from my system which triggered a memory of a week long fast from several years ago. Self-induced, of course. Along around day four, I remember that acrid taste. So the system is purging.