Picky eating behaviour is primarily influenced by genes and is a stable trait lasting from childhood to early adolescence, according to a UCL, King’s College London and University of Leeds study into eating disorders supported by MQ.
The study, published in the Journal of Child Psychology and Psychiatry They compared the results of a survey of parents with identical and non-identical twins in England and Wales aged between 16 months and 13 years.
The research team found that average levels of picky eating remained relatively stable over this period, peaking around age seven and declining slightly thereafter.
They concluded that genetic differences in the population explained 60% of the variation in picky eating at 16 months, increasing to 74% and higher between three and 13 years.
Environmental factors shared between twins, such as types of foods eaten at home, were found to be significant only in early childhood, whereas environmental factors unique to each twin (i.e., not shared by co-twins), such as individual personal experiences (e.g., having different friends), became more influential in later years.
Picky eating describes the tendency to eat a small variety of foods, due to selectivity about textures or flavors, or a reluctance to try new foods.
Lead author and MQ academic Dr Zeynep Nas from UCL said: “Fussy eating is common among children and can be a major source of anxiety for parents and carers, who often blame themselves for this behaviour or are blamed by others.
“We hope that our finding that fussy eating behavior is largely innate may help alleviate parental guilt. This behavior is not a result of upbringing.”
“Our study also shows that picky eating habits are not necessarily just a ‘phase’, but can follow a persistent trajectory.”
The research team analysed data from 1,927 pairs of twins from the UCL-led Gemini study, the largest cohort of twins ever created to study genetic and environmental contributions to early growth.
Parents filled out questionnaires about their children’s eating habits when they were 16 months, three, five, seven and 13 years old.
To separate genetic from environmental influences, the researchers compared the similarity in picky eating habits between pairs of nonidentical twins, who share 50% of their genes, with the similarity between pairs of identical twins, who share 100% of their genes.
They found that non-identical twin pairs were much less similar in their picky eating than identical twin pairs, indicating a strong genetic influence.
The team also found that identical twin pairs became more different from each other in their picky eating habits as they aged, indicating an increase in the role of unique environmental factors at older ages. (Any differences between identical twin pairs are due to unique environmental factors, as identical twin pairs share both their genes and certain aspects of their environment that make them more similar to each other.)
Lead author Professor Clare Llewellyn, a member of the MQ, said: “While genetic factors are the predominant influence on fussy eating, the environment also plays a supporting role.
“Shared environmental factors, such as sitting together as a family to eat, may only be significant in early childhood. This suggests that interventions to help children eat a wider variety of foods, such as repeatedly exposing them to the same foods on a regular basis and offering them a variety of fruits and vegetables, may be more effective in the early years.”
The researchers estimated that unique environmental factors explained about a quarter of the individual differences among children with picky eating behaviors between ages seven and thirteen.
Meanwhile, shared environmental factors explained a quarter of individual differences between children in picky eating at 16 months, with a negligible effect in later years.
Lead author Dr Alison Fildes (University of Leeds) said: “Although fussy eating behaviour has a strong genetic component and can extend beyond early childhood, this does not mean it is fixed. 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 adolescence.”
Among the study’s limitations, the researchers noted that there were fewer participants at age seven (703 children) compared with other times and that the study sample had a large proportion of white British households from higher socioeconomic backgrounds compared with the general population of England and Wales.
In the future, the team said, research should focus on non-Western populations where food culture, parental feeding practices and food security may be quite different.
The study involved researchers from UCL Behavioural Science & Health, the University of Leeds, King’s College London, South London and Maudsley NHS Foundation Trust, and the University of Cambridge.
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