The impressionable nature of preschoolers makes it easy to help them get used to good eating habits. Since they grow at a lower rate than infants, they need enough calories for their play and growth. You will overwhelm their small appetite by feeding then a lot of food. Get their cues right and give them just enough well balanced food.
Making meal times enjoyable will make meal times pleasant for preschoolers. Do not forces your preschoolers eat unwanted food. Avoid feeding your preschoolers with lots of juice and sweets during meal times. Stay with them even if you are not eating. Encourage them to eat. It will also help involving them in certain stages of food preparation that they can handle.