“Bread is Satan,” Eve Ensler declares definitively early on in the production of The Good Body, her one-woman show and follow-up to the wildly popular Vagina Monologues, now playing at the Lincoln Theatre. As she nevertheless waxes on about the joys of bread and dismisses such derivatives as flatbread as the mere “memory of bread,” Atkins aficionados, South Beach slaves, and whole-grain worshippers in the audience can’t help but grin with understanding. The tension between…