My son's the same went from eating loads of different things to just eating bananas and yoghurt as well as his formula for a week!
We found that the more we fretted about it the worse his eating fads got, so now we take the attitude of 'if he's hungry he'll eat' and it works he will now come and sit at the table and eat his luch/dinner. The staff at the nursery he goes to say he has the best table manners and eating habits of all the children in his age group, even my mum has made comments that he's really good when they take him out.
Smoothies seem to work really well if you are concenred about fruit intake and even a juicer too, Jnr. really likes carrot and orange juce and loves the colour of beetroot juice!
Just gently persist and try lots of different food, patience really is a virtue!
)Be careful she doesn't transpose this onto the child.
