I think Amanda was exercising some "dramatic flair" with her low blood-sugar incident. Ok, I'm a jaded cynic, but someone else has a medical issue, so immediately she is so faint that she passed out while walking in front of the diary room - but my hubby is an EMT and he said "that wasn't real" because she braced her fall with her hands when she allegedly "passed out" so she didn't smack her face on the floor. It was the most graceful "passing out" ever. I don't know, given the way she over-dramatizes every damn thing, I think she may have been feeling a little crappy with low blood sugar, but was totally playing it up for attention. Also, they said she was hypoglycemic, which is low blood sugar, but didn't indicate that she'd diabetic. I don't think they'd have someone with actual diabetes on the show, or at least not on just slop without some "leveling" foods (and insulin shots available, and test strips, etc.). A truly diabetic person can easily pass out or even slip into a coma, but they'd usually break their nose and knock out some teeth while falling on their face. I think Allison's medical situation was much more "real" just because she went to the diary room without calling attention to herself.
I'm sure I'd give her more benefit of the doubt if she wasn't such a drama queen, annoying voiced biach. There, I've said it. Bueno.