I've been to CityZen 2x now, once shortly after it opened (in Feb) and just this week. Both times I did the offered tasting menu and wine pairings. My spouse and I are definitely eaters and drinkers - I'm no lettuce leaf girl - but both times I was borderline ill from the quantity and richness of the food by the time the meat course rolled around (I think around course 5 of a 7 course meal - cheese and dessert to follow).
I suppose you could say its my fault for eating what is put in front of me, but every other tasting menu I've ever had was carefully apportioned so that when you finished you were just pleasantly stuffed (or even still hungry, which people say about French Laundry; I've never been). Seems like they ought to recalibrate the offerings, either by portion control or by how rich each course is, so that one can actually eat the whole tasting menu.
BTW, the food was quite good, and everything had exquisite flavor - it was just so rich that it felt like a job to keep going. Not a vegetable in sight!