We have moments from hell here too where they will eat a whole bowl of something one week and both turn their dainty particular noses up a week later. SO frustrating.
One thing I read on another thread recently was making the lunch meal a big substantial one rather than dinner. Then dinner could be whatever you know they will eat - even a sandwich or something? I do that on some days and if I know they have had a great lunch and pick at dinner they ust have fruit and yoghurt and we leave it at that. Both of mine are string beans but eat relatively well over the day aw well.... James will spit out meat if it's too tough as well (and sometimes not even when it's tough, like he cbf chewing ) Have you kept a food diary hun just to reassure yourself that they probably are getting all they need and it you mix things up a bit it will be fine. As they get older I bet it will get easier. Iz was a shocker too and is VERY slowly getting better but J at 2 can border on the ridiculous. xoxox