"Not just a phase": Fussy eating is mainly influenced by genes and is a stable trait

By Priyanjana Pramanik, MSc.Reviewed by Danielle Ellis, B.Sc.Sep 24 2024

A new twin study finds that food fussiness is largely driven by genetic factors, with over 70% of influence coming from genes. 

In a recent study published in the Journal of Child Psychology and Psychiatry, researchers explored how food fussiness (FF) is influenced by genetic factors (‘nature’) and environmental contributors (‘nurture’).

Their findings indicate that individual differences in FF exhibited by children across all ages are related to genetic factors. However, fussy eating in toddlers may be influenced by environmental factors, making this time critical for interventions to address FF.

Background

Many children are picky about the texture or flavor of their food and may be reluctant to try unfamiliar foods, leading them to eat a limited number of items. FF often appears in toddlers, peaking between early and middle childhood and fading as children grow into adolescents. Some experts believe it may be experienced by up to 50% of children.

Children who do not grow out of fussy eating may suffer from several adverse psychological and physical health issues, including food-related anxiety, nutritional deficiencies, and faltering weight. As they grow into adulthood, they are at a higher risk of eating disorders. The effects are also felt by their families, who may struggle with anxiety related to feeding their children and disrupted mealtimes.

Understanding how nature and nurture interact to influence FF can help researchers understand how to manage these behaviors and when interventions will be most successful.

About the study

Researchers aimed to model how fussy eating develops between toddlerhood and early adolescence and examine the contributions of nature and nurture to individual differences.

Twins are more genetically similar to each other than other sibling pairs, with identical twins having a higher degree of similarity than fraternal ones. Comparing FF behaviors between identical and fraternal twins who experience similar environmental conditions allowed researchers to differentiate the impact of environmental and genetic factors.

They contacted 6,754 eligible families with twins, of whom 2,402 families participated in the baseline survey. The survey included information on eating behavior and appetite, growth, health outcomes, and home environment. The study began when the children were 16 months old and ended when they were 13.

To understand eating behavior, researchers asked parents questions such as whether their children decided that they did not like food before they had tasted it, with options for answers ranging from ‘always’ to ‘never.’ The degree of genetic similarity between the twins was also calculated.

Findings

The results showed that children who started with higher FF scores often had larger increases in fussy eating behaviors over time in the linear analysis. However, they were also likely to exhibit faster declines in FF behavior between the ages of 7 and 13. Overall, between 74% and 79% of differences among individual children could be explained by ‘nature’ or genetic factors.

Correlating FF traits between twins suggested that genetics plays an important role in FF behaviors at all ages. Specifically, identical twins showed more than double the correlation exhibited by fraternal twins, who have less genetic similarity.

Researchers also found that FF traits are highly heritable across all ages and that the importance of genetic influences can increase with the children’s age, from 60% at 16 months to 84% by 13 years of age. Meanwhile, environmental influences were only significant at 16 months of age, with an importance of 25%.

Advanced analysis indicated that genetic factors best explain the stability of FF over time. However, some new genetic influences emerged during adolescence. Shared environmental factors showed minimal effects on the stability of the trait. Though the importance of non-shared environmental influences increased with time, they were less important than genetic factors.

Conclusions

This study adds to a body of research evidence that children may show enduring and persistent behaviors related to fussy eating. On average, children in the study showed more FF behaviors when they were 13 than they did when they were 16 months old.

While the genetic basis for FF traits may alleviate the distress felt by parents and caregivers, the significant role of environmental factors during toddlerhood may allow health and nutrition professionals to develop effective family-based or environmental interventions during this time.

While behavioral interventions may not successfully address FF, they are most likely to be effective during this time. These could include gradually increasing the amount of vegetables and fruits offered to the child through techniques such as repeated exposure.

The study’s results provide the most comprehensive insights into fussy eating among twins over time, but as with other longitudinal surveys, it suffers from attrition in responses over time. Further studies with large samples are needed to shed further light on this important aspect of child development.