Parents who find themselves exasperated by their child’s fussy eating, take heart: the refusal to tuck into a broader range of foods is largely down to genes rather than parenting, according to scientists.
Researchers investigated eating habits in toddlers to teenagers and found that on average fussiness over food changed little from 16 months to 13 years old. There was a minor peak in pickiness at seven years, then a slight decline thereafter.
When they looked into the drivers of fussy eating, DNA emerged as the dominant factor. Genetic variation in the population explained 60% of the differences in pickiness at 16 months, rising to 74% and more from three to 13 years old, the study found.
The finding suggests that eating only a narrow range of foods and grimacing at the prospect of trying something new are more down to nature than nurture. It also points to windows of opportunity when interventions to encourage a more varied diet might be more effective.
Dr Zeynep Nas, a behavioural geneticist at UCL, said: “The main takeaway from this work is that food fussiness is not something that arises from parenting. It really does come down to the genetic differences between us.”
Other factors that influence fussy eaters come from the environment they live in, the researchers said, such as sitting down to eat as a family and the kinds of foods consumed by the people around them.
Nas and her colleagues analysed data from the UK Gemini study, which enrolled 2,400 sets of twins to explore how genetics and the environment affect childhood growth. As part of the study, parents completed questionnaires on their children’s eating habits at 16 months and again at three, five, seven and 13 years old.
To work out how much genetics contributes to fussy eating and how much is down to environmental factors, the researchers compared the eating habits of identical twins and non-identical twins. While identical twins share 100% of their genes, non-identical twins share only half.
Writing in the Journal of Child Psychology and Psychiatry, the researchers describe how fussy eating habits were more similar among identical twins than non-identical twins, evidence that genetics largely underpinned differences in pickiness.
But the children’s environment also mattered. Experiences that twins shared, such as the kinds of food eaten 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% of the variation in fussy eating levels.
Shared experiences, such as eating as a family, were most influential in toddlers, so offering more variety around that age might be most effective, the researchers said.
While genetics is clearly important in fussy eating, it should not leave parents feeling disempowered, the researchers add. As Nas puts it: “Genetics isn’t destiny.”
Dr Alison Fildes, a co-author of the study at the University of Leeds, said: “Although fussy eating has a strong genetic component and can extend beyond early childhood, this doesn’t mean it is fixed.
“Parents can continue to support their children to eat a wide variety of foods throughout childhood and into adolescence, but peers and friends might become a more important influence on children’s diets as they reach their teens.”
In 2022, Dr Nicola Pirastu at Human Technopole, an Italian research institute, led a study into the genetics of food preferences.
He found that genetics affecting taste and smell receptors were less important than variations in the brain which affected how people reacted to different flavours. “Although flavour is the first driver of food choices, genetic differences are more likely to determine how the brain responds to them,” he said.
Understanding more about the genetics of food choices could help scientists identify what deters some people from eating healthily and pave the way for modified healthy foods that are more appealing, Pirastu said. Another possibility, he added, is a new generation of drugs that shift people’s preferences towards healthier foods.
