Can absolutely relate to this. Our eldest daughter is a pain in the backside when it comes to eating - very similar to the hurdle you describe.. but sit her down with her cousin and whatever he eats, she does too.. and "its my favourite" is all we hear.Social eating is effective. Not with us, but at nursery. He eats a lot better with other kids.
Also found that if she gets to "help" prepare the food she is more likely to say she enjoys it.. most of the time we've found its psychological warfare rather than any underlying health issues.. between 2 & 4 kids push the boundaries like mad
