Please help my 3year old has less than 400kl per day!!!?

Perhaps hes learned to ociate food with anxiety. If you push them too hard to do something they may react to it in a negative way. Because hes an older toddler now you need to get help from a child behaviourist or psychologist straight away rather from a dietian this seems pretty urgent to me as it looks more than just fussy eatting. I think you can get medicine from the doctor so that they get more hungry and eat. Theres a toddler vitamin syrup from tescos called wellbaby that he can take so that he has some nutritian.