I've been using all my march 13 ones, as like you I've returned back to s & s and wanted to use 40+ packets. I've been using them for the past 2 weeks n had no ill side affects & I don't think it's halted my weight loss either (12 lb 1st week, only 2lb this week though). I do think the meal packs taste very powdery though, don't remember them tasting quite as bad 1st time round. Shakes, soups and bars all taste ok. Xx