Crux of emotional overeating

Comfort eating is triggered by nurture, not nature, according to Moritz Herle, Alison Fildes, Clare Llewellyn and Steinsbekk Silje

THE portrayal of a heartbroken woman devouring a tub of ice cream under a duvet is a well-established television cliché. That’s probably because it’s actually quite a common behaviour.

You may be all too familiar with the scenario: you’ve had a particularly gruelling day at work, or you’re in the throes of a devastating breakup and you reach for your favourite food for comfort. Scientists call this tendency “emotional overeating”.

The problem is that it increases your risk of becoming overweight: regularly eating a large number of additional calories for reasons other than hunger will do your waistline no favours.

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.

To find out more, we recently conducted two studies of emotional overeating in children from the UK and Norway.

In one study of British twins, we looked to see if this tendency is shaped more by our early environmental experiences, or genetic predisposition. In the other study of Norwegian children, we looked to see if parents play a role by offering food as a source of comfort to their young children.

A powerful method for understanding how genes and environments shape our traits is comparing identical and non-identical twin pairs.

Identical twins share 100% of their genes, while non-identical 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 large 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.

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 been hurt. 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 years old.

Our analysis of the results showed that emotional feeding does encourage 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 that it can be prevented. We need to help parents find alternative strategies for comforting distressed children.

This article was first published on The Conversation.

Moritz Herle is a PHD candidate at the Department of Behavioural Science & Health, University College London, UCL; Alison Fildes is a University Academic Fellow, University of Leeds; Clare Llewellyn is a lecturer in Behavioural Obesity Research, UCL; Silje Einstein is the associate professor, Norwegian University of Science and Technology