Sometimes it can be a gentle, off-the-cuff and entirely innocent remark that's made... sometimes it's something a little bit more pre-meditated or non-subtle, but the truth is, talking to an ED-sufferer is a total tightrope.
Even something as simple as someone saying "you look healthy today" - mum said this to me the other day meaning "You don't look drawn and jaundiced" but I took it as "wow, how's it going, Whale Boy? All-You-Can-Eat Plankton Buffet, was it?"
The truth is, sometimes we don't even understand ourselves what a compliment is, or how it feels. For so long things have been a binary "thinner equals better, heavier equals worse" thing, and we forget that this is not at all true.