Many children do not like some vegetables. How can they learn to like them? In a British study, parents gave their young children one small taste of a disliked vegetable every day for 14 days.

After that, the children liked the vegetable more and ate more of it. Other parents only got advice about healthy food. Their children improved less. Tasting again and again worked best.

Young children are often afraid of new foods, which may once have protected humans from eating poisonous plants. However, research shows that this fear can change. In 2003, Jane Wardle and her team in London studied 156 parents and their 2- to 6-year-old children. Each child first chose a vegetable they disliked, and the families were then randomly divided into three groups.

In the first group, parents offered a small taste of it every day for 14 days. In the second, parents received nutrition advice, and the third group did nothing. Only the tasting group showed clear increases in liking and eating the vegetable. Simply explaining that vegetables are healthy did not work as well as repeated tasting.

Young children are often wary of unfamiliar foods, a tendency that may once have protected our ancestors from toxic plants. But this reluctance can change. In 1982, the American psychologist Leann Birch showed that two-year-olds came to prefer unfamiliar foods the more often they tasted them. Her paper had a memorable title, "I don't like it; I never tried it." Building on this idea, a 2003 randomized trial led by Jane Wardle in London recruited 156 parents and their children aged two to six.

After each child chose a disliked vegetable, the families were randomly assigned to three groups, and parents either offered a small taste of it daily for 14 days, received nutrition advice and a leaflet, or did nothing. Only the taste exposure group showed significant gains in liking, ranking and intake of the vegetable. The advice group improved less than the taste exposure group did. Repeated exposure is thought to work by building a sense of safety and familiarity.

Researchers stress that the tastes should be offered gently and never forced. Wardle's follow-up was short, and there is little evidence on children with extremely picky eating. Even so, a 2018 review concluded that taste exposure is the most consistently effective approach for preschoolers.