I see you already had lots of support but I couldn't read and not post. Mine also went right off food during certain teething phases (not all but some), here it could last several days and through those days I gave him anything he wanted that was still considered healthy. So I wouldn't usually give just sultanas or grapes for lunch because I don't consider that a balanced diet even though it's healthy food but if that's all he'd have when teething then fine, have them.
Mine loved something hard to chomp on, bread sticks he'd snatch at, and (not sure if they have these where you are) some sugar free baby/toddler biscuits I think they are 'Goodies' moon biscuits, quite hard. I think it's like a teether, something hard to gum can actually ease the pain.
Raw celery (a long stick so the strands can be held comfortably, not cut into little bits) is something I always suggest as it has natural local anaesthetic qualities but so far I've never heard of any LO accepting it
When the teething pain has passed she'll likely make up for any lost calories and eat your fridge empty. Try not to worry.