There is no scientific definition of picky eating, but parents say they know it when they see it, and according to new research, they are likely to be right. Their kids are different. But picky eaters are not all the same, this study finds. What parents call picky eating is actually a broad spectrum of behaviors, and knowing which category a child falls into may help parents develop constructive responses.

The researchers gathered 170 two- to four-year-olds, about half of whom were described by parents as choosy. For two weeks the parents fed the family standardized meals provided by the investigators. The parents observed and recorded their children's responses.

Nonpicky kids ate more and did not make a fuss about eating. Those seen as picky acted differently before and during meals, with behaviors that ranged from refusing to come to the table, to showing mild suspicion of certain foods, to cringing or gagging.

From focus groups with parents, says study co-author Sharon M. Donovan, a professor of nutrition at the University of Illinois at Urbana-Champaign, the researchers identified four possibly overlapping categories of behavior that could cause parents to identify their children as picky eaters.

Some of these preferences, such as shunning broccoli, Donovan notes, may be hardwired. Research indicates that some children are genetically more sensitive to bitter flavors than others and may therefore take longer to acquire a taste for certain vegetables. Other mealtime antics, such as looking sad or even gagging, may not have to do with the food at all—for example, a child may be upset that she had to stop playing but attempts to express her independence by refusing to eat, explains study co-author Soo-Yeun Lee, also a nutrition professor at Illinois.

Picky eating is not uncommon: Donovan says that 19 to 50 percent of kids up to age two, when the phenomenon peaks, are considered finicky eaters by their caregivers. How parents react can influence its staying power.

The researchers do not yet have scientifically validated strategies for each kind of picky eater, but Lee says it may help parents to recognize that their kids' reaction to mealtime may not always be about food or eating. As such, it does not make much sense for parents to get into power struggles with youngsters about eating—especially because the behavior usually goes away or lessens after age five.

Until they develop more targeted approaches, the nutritionists recommend a few time-tested strategies. For a child who does not like mixed foods, show him or her the individual ingredients the first time you serve the item. Acknowledge that your child has preferences but serve foods that are deemed unacceptable along with favorite foods. Don't force your child to eat something new but encourage him or her to take a taste. Most of all, keep trying, Donovan says. “Children may need 10 exposures to a new food before accepting it. Parents often give up before then.

Four Types of Finicky Eaters

Sensory-dependent eaters reject a food because of its texture or smell (“Yuck, slimy!”).

Preferential eaters shun new or mixed foods.

General perfectionists have specific needs, such as foods not touching one another.

Behavioral responders may cring or gag when right is not “right” (“Ham and cheese should be on white bread, not brown!”) or may refuse to come to the table before they even know what’s for dinner.