Offering fruits for snacks and serving vegetables at dinner can shape a preschooler's eating patterns for life. (CBC)

Showing parents how to make their homes a place where children will reach for a banana instead of chips could help preschoolers learn to eat healthier, researchers say.

In a five-year study in rural southeast Missouri, two groups of parents were randomly assigned to participate in either a nutrition education program or a standard education program.

Since earlier studies have shown children to like and eat vegetables before age five, the study on 1,300 families focused on that age group.

Both groups received visitors, but the nutrition group received examples of how to teach children the names and colours of various fruits and vegetables, as well as handouts with suggestions for improving the family's diet.

During four visits, children were able to choose a variety of fruits and vegetables for breakfast, as well as singalong stories and colouring books.

After an average of seven months, the team from Washington University in St. Louis found parents ate significantly more fruits and vegetables, and it paid off for their kids.

When mom or dad ate one more serving of fruit or vegetable per day, the child tended to eat half a serving more, if they were of normal weight, the researchers reported in the July issue of the journal Preventive Medicine.

"Overweight children have already been exposed to salty, sweet foods and learned to like them," said study author Debra Haire-Joshu, a professor of social work.

"To keep a child from becoming overweight, parents need to expose them early to a variety of healthy foods and offer the foods many times," she added in a release.

The nutrition education program, called High 5 for Kids, aims to help children learn to eat healthy and practise what they've learned, Haire-Joshu said.

"H5-KIDS suggests the need for, and promise of, early home intervention for childhood obesity prevention," the study concluded.