Comfort eating is triggered by nurture, not nature
THE PORTRAYAL of a heartbroken woman devouring a tub of ice cream under a duvet is a well-established television cliché – think Bridget Jones. That’s probably because it’s actually quite a common behaviour: 38% of adults say they eat more when stressed or sad.
Scientists call this tendency “emotional overeating”.
We know from previous research that a tendency to eat for comfort begins in early childhood, but we know very little about where this actually comes from, especially during the important formative years.
Fixing the problem
A powerful method for understanding how genes and environments shape our traits is comparing identical and nonidentical twin pairs.
Identical twins share 100% of their genes, while nonidentical twins share about half of their genes – the same proportion as regular siblings. But both types of twins are raised in the same environment and share similar experiences. Researchers can therefore compare how similar the two types of twins are to establish the extent to which genes and environments shape emotional overeating (or any other trait of interest).
If identical pairs are more similar to each other in behaviours (such as emotional overeating) than non-identical twin pairs, this indicates that genes play a role. However, if both types of twins show equivalent similarity, it can be implied that the environmental experiences shared completely by twin pairs, such as upbringing, are more important in influencing behaviours.
To find out about the role of genes and environments in shaping emotional overeating in childhood, we analysed data from the Gemini study, a study of over 2 400 British families with twins born in 2007. Parents rated their twins’ tendencies to emotionally overeat when they were toddlers (16 months), and again when they were five years old. Results showed that the most important influence on the tendency to comfort eat as a child was the environmental experiences shared by twins. Genes were unimportant.
Using food to soothe
Early environmental experiences that lead to comfort eating are likely to involve early feeding experiences. Many parents use food to soothe their child’s distress – such as offering a favourite food for comfort when their child has hurt themselves. Researchers call this “emotional feeding”. But using food to soothe may inadvertently teach the child to apply the same tactics themselves when in distress.
A child who is repeatedly fed when he or she is upset or expresses negative emotions learns that eating helps to regulate emotions, and so might learn to comfort-eat. To test this theory, we studied parents’ emotional feeding and their children’s emotional overeating in nearly 1 000 families from Trondheim, Norway.
Parents rated their tendency to offer their children sweets or snacks to calm them down or cheer them up, as well as their children’s tendency to emotionally overeat. Parents answered these questions several times when their children were six, eight and 10.
Our analysis of the results showed emotional feeding predisposes children to emotional overeating tendencies. Children whose parents often used food to soothe them displayed more emotional overeating as time went on.
The discovery that comfort eating in childhood is learnt, not inherited, suggests it can be prevented. We need to help parents find alternative strategies for comforting their distressed child, such as offering a favourite TV programme or game rather than a fizzy drink.
Herle is a PhD candidate at the Department of Behavioural Science and Health, University College London, UCL; Fildes is a university academic fellow, University of Leeds; Llewellyn is a lecturer in behavioural obesity research, UCL; Steinsbekk is associate professor, Norwegian