Sniffs, my DD would have starved herself if I did that, seriously. So would I as a child. Even now there are foods j just can't bring myself to eat - peas, sprouts and green beans mainly. I hate the bitter taste. I also dislike tomatoes (though am fine with them cooked) and beetroot.
People forget that a child's palate is different to an adults. There are dozens of foods that I enjoy now that I hated as a child. I used to find melon really sharp tasting and now I love it and find it fresh and sweet. I also hated French bread because I didn't like chewing it so much and it got 'stuck' in my throat. Hated mushrooms which I think is another common one for children - I disliked the texture. Again, I love them now. I hated cheese (it's still not my favourite thing but I am partial to a cheese and pickle sandwich.) I disliked a lot of fruit as well - anything citrus, nectarines and peaches (again I love them now) and salady stuff like peppers and cucumber and onion. I now love peppers and onions but still not a cucumber fan.
Obviously we all really want our children to have a healthy and balanced diet but the worst way of doing this is to essentially starve them - it doesn't work and it makes them likely to store up on carby and sugary foods because they are peckish. Much better to provide a balanced meal they will eat. My daughter, for instance, likes sweet potato and she has this mashed with carrot and some swede and a bit of cheese - that with a couple of veggie sausages and baked beans is a nice tea for her as its warm, filling, has veg and so on.
It's worth remembering for fussy eaters bland and sweet is the way to go. So the perfect green veg is spinach hidden in mash. The best veg are sweet ones - carrot and sweet potato. Cheesy sauces hide things.
Custard, yoghurt and rice pudding (calcium) are also good if you've a milk refuser. Some children might enjoy yogurt and a bit of honey with berries as a relatively healthy but sweet snack. Fruit and custard is lovely.
Some children are intimidated by big portions - I always was - cutting up small amounts of food and topping it up later can help.
Swede chips are nice and healthy, too. At times it is just about running with a phase. But the worst thing you can do is to have the inflexible attitude 'eat it or be hungry.' It turns food into a battle of wills, into something to be dreaded rather than enjoyed and ultimately can lead to both unhealthy eating and unhealthy attitudes.