My oldest daughter use to be what I call a "no" reaction child. Whenever I would present anything new to her food or anything else "new" her first reaction was always no. I realized this when every morning I would put down breakfast and she would say, "I hate that" no matter what it was, even her favorite chocolate chip banana muffins! I then realized that the transition to from sleep to awake was hard and so no matter what I put in front of her the answer was no! This applied to food as well. When ever I would give her something new she would say, "No, I am not going to eat that."
So, on day I sat her down and explained to her my definition of a "no" reaction child. I told her that I had noticed that when ever I gave her a new food she automatically would say "no" before even trying it. I told her that her tongue may just change its mind about the foods if she would just keep trying. I introduced a new game to her...Table Baseball!
This is how I explained it to her: To play Table Baseball you have to try a food 3 times. The first bite you get to give it a strike if you do not like it (a base run if you do), then you take a second bite and if their tongue has not yet changed its mind and the food still doesn't taste good that is strike 2 (if it tastes better the second time then we call it a double), then you repeat it one more time and with the 3rd try either the food gets a hit (tripple or home run) and they eat it all up or strike 3 and it is out and they do not have to eat any more!
I found the more we played this game the more her tastes did begin to change, her tongue really did change its mind. Before we knew it we were getting, singles, doubles, and home runs instead of strikes!
Don't give up- keep giving them the healthy stuff, they will learn to like it!