I've found that my kids are more prone to eat healthy if they've had some level of involvement in the selection, planning or preparation of food.

For example, we went strawberry picking this weekend. And not that they need any convincing to eat strawberries (as they love them), seeing how they are grown, deciding which are ripe and which are over-ripe, all this helped them to connect nature and the outdoors with healthy eating. I think seeing how food is grown and collected is fascinating for a child and we were all excited to get home and wash our beautiful bounty so we could feast on the delicious berries.

I also try to have them help with cooking as much as their little hands can manage. They love cracking open eggs and on the weekends we make a big breakfast at least one of the two days. Omelets or pancakes, they are excited to assist with whatever menu we decide on. I've found them to be much more interested in eating when they have participated in the preparation.