DD is seven, we constantly get told "what a marvellous eater" and "doesn't she enjoy her food?" and "It's so nice to have her round, she eats everything".
Yes, but the PAIN of nearly 3 years not letting her dictate meals, and not offering alternatives, and saying "no pudding" and "eat your veg" oh it was hard, but we now reap the rewards, as does she, she gets to go to all sorts of restaurants and enjoys her food.
The only thing we allowed was, she hates potato, I mean really hates it, so we don't offer her potato or force her to eat it, she gets rice instead. I don't think children should be forced to eat something they really don't like, but we always insisted she tried everything (yes, bribery was involved in extra pocket money for the short term). As a result of "trying" things she loves swede and cabbage and shovels it down. I don't know many 7 year olds who do that!!!
So I agree with not letting them dictate their own meals and not restricting their diet.
And we don't have biscuits in the house, so she can't have one. Phrases such as "you should eat your meal then you wouldn't be hungry" got used a lot. You just have to have teh will power to resist the constant whining. They stop whining once they realise it gets them nowhere, but you ahve to get through the incredible level of whining they produce.