Hi, i dont know what to do anymore so i thought...

Hi, i dont know what to do anymore so i thought someone else with a fresh perspective might have better ideas. my partners 3 yr old daughter wont eat stuff all come dinner time it doesnt matter if you dont give her attention while shes eating or give her attention she wont eat, any vegetables even meat she wont eat she only wants potatoe or spagetti. I dont cook seperate meals for her, i have tried pureying up her veges and putting them with potatoe or the spagetti she knows they are there so wont touch it, briery doesnt work, praising her when she eats all her dinner doesnt work although we still do it in hope of some change. the biggest thing for me is at the moment because she is not eating shes not eatting enough vitamins and minerals i am having to put her on supplements because her hair is falling out i dont know what to do anymore every strategy my family has givin me hasnt worked nor the docters strategys. Aparently because she is so young and likes the control over her food it means that she will be more likely to become bulemic or anorexic when shes older i dont know how to help her so she doesnt end up like this. Any adivce would be appreciated.