My DD#1 at around 18 months of age refused to eat anything. I attempted to go back to work for 2 days per week, and my mother looked after her. I remember days when i would pick her up and mum would say 'she only ate a biscuit today' . YOu wonder how they survive, and what they're insides are doing !! But you would be amazed at what children live on. She has just turned 3 and is a good eater. I suppose your concerened with the nutrional aspect. Your daughter is doing well - milk, weetbix, zucchini. My DD isnt a big meat eater either..... I read somewhere that toddlers can become very lazy with food, especially with meat; meat can often take too long to chew and swallow - there's more important things to do - for them anyway. I now cut up a lamb cutlet or a chop into bite size pieces. She seems to enjoy that.
I know its not very reasurring, but i found it was a phase my DD went thru.