Exactly what the HV said, I phoned my HV today about exactly the same thing!!
My daughter is 3 and the worst picky eater ever! I'm at the end of my tether with her, I made all my own food when I weaned her, she ate everything I gave her, fruit, veg, meat etc, turned 18 months and refused everything!
She has an extremely limited diet at the moment, even refusing foods she usually likes? I've tried ... diguising, bribing, shouting, reward chart, everything! Nothing works, so today the HV said she has got control and is loving it, she wants attention and is getting it whichever way she can! (I've been told all this before but didn't follow it)!! 
So this is what she said to do and it does make sense:
If you know he/she will only eat 1 chip and 1 fish finger and four peas, give them that, its all about praising them for clearing their plate, not finishing their food as its normal to eat food!!
Put the plate on the table, either eat with them or sit with them, say nothing so no cajoling, just eat one more bit etc! SAY NOTHING about the food (so hard not to)!! Talk about their day, what they have done, what they are doing tomorrow etc, but don't mention food! After half an hour, ask them if they have finished and take it away.
Even if they don't eat a thing, they can still have 'pudding' but only a yoghurt or a piece of fruit, no 'goodies'.
There is to be no other food until snack time, has to be a gap of at least two hours before main meal again, snack is to be cheese, fruit, no goodies! Oh and no milk in the day only morning and night.
So after a disastrous lunch, an hour later she said she was hungry, I made her wait another hour and gave her a banana, nothing else. She then had 1 fish finger, 1 chip and some spaghetti hoops at 5 and ate most of it, never said a word about the food and it seemed to work??
HV also told me to put her on Minadex for the iron as she is such a poor eater, I just put it in her milk at night and in the morning?
Hope this helps? Good Luck!! 