We're just getting in to the joyous stage of the almost-toddler starting to refuse certain foods, generally on principle because what she doesn't like one day she will adore the next 
I'm not sure how much choice to offer, though, if one bit of food is refused. For example, yesterday at lunch she only picked at her main, then refused the extra veg (normally a huge favourite) and ate the usual yoghurt dessert. As she had barely eaten anything I have her some rice cakes as well. We were thinking that if she refuses the main food, then what she gets eventually offered instead is much less 'interesting', though I don't know if that's the right approach. But when she finally got down from the highchair (having thrown a lot of the rice cake on the floor) she was clearly still very hungry, crying for food, and too unsettled to be left, so I gave her some fruit which she ate loads of.
She's 15mo and though she still loves her milk, she only has 14oz a day and it is well spaced out away from her meals. I don't mind her not eating much if she's just not hungry, but I'm not sure what's the best approach if she is hungry but is determindly rejecting everything that is offered. Any tips would be great, thank you!