Parents who are annoyed by their child’s picky eating habits can rest assured: according to scientists, the refusal to eat a more varied diet is largely due to genes and not to upbringing.
Researchers examined eating habits from toddlers to teens and found that picky food changed little on average from 16 months to 13 years of age. There was a small peak in pickiness at age seven, then a slight decline.
When they looked at the drivers of picky eating, DNA emerged as the dominant factor. Genetic variation in the population explained 60 percent of the variation in pickiness at 16 months, rising to 74 percent and more from ages three to 13, the study found.
The finding suggests that eating only a limited number of foods and grimacing at the prospect of trying something new may have more to do with nature than nurture. It also points to opportunities for when interventions to encourage a more varied diet could be more effective.
Dr Zeynep Nas, a behavioural geneticist at UCL, said: “The main lesson I’ve learned from this work is that being picky about food isn’t something that comes from parenting. It really comes down to the genetic differences between us.”
Other factors that influence picky eaters, according to the researchers, have to do with the environment they live in. For example, eating together as a family and the type of food the people around them eat.
Nas and her colleagues analyzed data from the British Gemini Study, which included 2,400 pairs of twins, to investigate how genetics and environment affect children’s growth. As part of the study, parents completed questionnaires about their children’s eating habits at 16 months and again at ages three, five, seven and 13.
To find out how much genetics contributes to picky eating and how much environmental factors, the researchers compared the eating habits of identical twins and fraternal twins. While identical twins share 100 percent of their genes, fraternal twins share only half.
Writing in the Journal of Child Psychology and PsychiatryResearch shows that picky eating habits are more similar between identical twins than between fraternal twins, evidence that differences in pickiness are largely due to genes.
But the children’s environments mattered, too. Experiences that twins shared, such as the types of food they ate at home, were important drivers of pickiness when they were toddlers. Between the ages of seven and 13, individual experiences, such as having different friends, explained about 25 percent of the variation in picky eating levels.
Shared experiences, such as eating together as a family, have the greatest impact on toddlers, so researchers say it may be more effective to offer more variety around that age.
While genetics clearly play a role in picky eating, it shouldn’t leave parents feeling powerless, the researchers add. As Nas puts it, “Genetics is not destiny.”
Dr Alison Fildes, co-author of the study from the University of Leeds, said: “Although picky eating behaviour has a strong genetic component and can extend beyond early childhood, this does not mean it is a fixed fact.
“Parents can continue to support their children in eating a wide variety of foods throughout childhood and adolescence, but peers and friends may become a more important influence on children’s diets as they reach teenage years.”
In 2022, Dr. Nicola Pirastu from Human Technopole, an Italian research institute, led a study in the genetics of food preferences.
He found that genetics that influence taste and smell receptors are less important than variations in the brain that influence how people respond to different tastes. “Although taste is the primary driver of food choices, genetic differences are more likely to determine how the brain responds to them,” he said.
Understanding the genetics of food choices could help scientists identify what keeps some people from eating healthy and pave the way for customized healthy foods that are more appealing, Pirastu said. Another possibility, he added, is a new generation of drugs that shift people’s preferences toward healthier foods.