In a pilot study, the Harvest for Healthy Kids programs helped preschoolers in Head Start centers be willing to try and to like foods like butternut squash, turnips and asparagus.

"We know that children develop their food preferences based on early experiences with foods, so it is important to introduce healthy foods in early years," said lead author Betty T. Izumi of Portland State University in Oregon.

"There's a general myth that kids don't like vegetables," but that's not necessarily true, Izumi told Reuters Health by phone.

Between fall of 2012 and spring of 2013, four Head Start centers in Portland, Oregon, implemented the Harvest for Health Kids program.

The "target" foods included carrot, butternut squash, sweet potato, cabbage, turnip, rutabaga, berries, beet, and asparagus, all prepared with simple recipes designed to highlight, not mask, their flavor. The researchers chose local, seasonal foods, as they would be more affordable and would taste best, Izumi said.

Two centers used a low-intervention form, which only included food service changes wherein the target foods were served twice per week as the fruit or vegetable component of meals.

The other two centers used a high-intervention form, with food service changes as well as nutrition education, with monthly activity kits designed to improve food knowledge through cooking activities, read-aloud book discussions and mealtime discussions. Teachers at these centers completed a four-hour hands-on training session before the intervention began and then a two-hour booster session.

Before and after the program, trained researchers assessed 226 participating children, who averaged about five years old, by offering them small samples of each target food.

In the low-intervention group, willingness to try the foods increased after the program for four of the nine target foods: cabbage, rutabaga, turnip and beet.

In the high-intervention group, willingness to try increased for every food. In this group, 55 percent of kids were willing to try rutabaga before the program and 84 percent were willing to try it after the program.

Among those who tried the foods, the number who said they liked it also increased for carrot, cabbage and berries in the low-intervention group and for carrot, rutabaga and berries in the high-intervention group, the authors reported in the Journal of the Academy of Nutrition and Dietetics.

"It makes perfect sense that the schools that got high intervention which included nutrition education had better results," said Abbie Nelson, the director of Vermont Food Education Every Day (VT FEED), a farm-to-school program connecting schools to local farms in the state. Nelson was not part of the new study.

"It's not just about throwing a rutabaga stick at a kid and saying, try this," she told Reuters Health by phone. "It's more about familiarity, what does rutabaga look like, smell like, feel like."

One of the key parts of teacher training involved role modeling. Even if the teachers themselves did not like the foods, they were directed to try it and find something interesting about the food to share with the kids, Izumi said.

"That could be, 'this is really crunchy, why don't you take a bite'," she said. "It's really important not to fake it."

"Parents influence children's food preferences more than anybody else," she said. "Even if children eat foods in preschool, after graduation, we need to continue to provide children with vegetables beyond that period."

It can be hard for low-income families to buy and prepare fresh vegetables, but persistence is key, Izumi said.

"If you have a picky eater, then you continue introducing the foods and serving them but in different ways, try roasting them," she said. "It's important not to hide vegetables."