DS2 (3) is a real carb monster, and is happy to reject all unfamiliar foods. This was getting me down, so last week I started shouting at meal time.
I get very very cross at both DSes for eating any vegetables. Lots of 'how dare you eat your vegetables! I am so angry!' and comical shaking of fists.
It works very well. DS1 thinks it's hilarious (he already was eating veg well), and DS2 is trying lots of things he wasn't trying before, and then saying 'say "boo" mummy'.