Writing in Psychological Science, the team behind the study examined the behavioural and neural responses to images of appetising unhealthy foods in children, adolescents and adults – finding that young children have stronger urges and cravings for foods, but that they are able to better use a cognitive strategy that reduces these cravings more effectively.
"These findings are important because they suggest that we may have another tool in our toolbox to combat childhood obesity," commented Jennifer A. Silvers of Columbia University, who led the research.
The team noted that currently, most interventions aimed at preventing or reducing childhood obesity focus on changing the environment – for example by limiting access to soda or by encouraging physical activity.
"Such environmental interventions are clearly important, but sugary sweets and tempting treats cannot always be avoided," Silvers said. "If children as young as 6 can learn to use a cognitive strategy after just a few minutes of training that has huge implications for interventions."
To investigate how food craving and regulating food craving change with age, Silvers and her colleagues had 105 healthy individuals come to the lab to participate in a neuroimaging session. The participants, who ranged in age from 6 to 23 years, were shown pictures of a variety of unhealthy but appetising salty and sweet foods while undergoing fMRI scans.
For some of the pictures, participants were told to imagine the food was in front of them and to focus on how the food tastes and smells. For the other pictures, they were told to imagine that the food was farther away and to focus on the visual aspects of the food, such as its shape and colour.
After viewing each picture, the participants rated how much they wanted to eat the food they had seen.
Having the participants imagine the taste and smell of the food allowed the researchers to assess the participants' typical responses to appealing foods, while having them imagine the visual aspects of the food, a cognitive strategy that redirects attention, allowed the researchers to assess how participants regulated their responses to the food, said the team.
Silvers and her team revealed that participants of all ages reported less craving when they used the cognitive strategy of imagining the visual aspects of the food - amounting to a 16% reduction in craving.
Even when using the strategy, however, children's food cravings were still stronger than those of adolescents and adults, suggesting that foods are generally more desirable to children, they reported.
An analyses of the neuroimaging data showed that age-related reductions in craving were associated with increased activity in the lateral prefrontal cortex, which is involved in self-control, and decreased activity in the ventral striatum, which is involved in reward processing.
The team also found that children with higher body mass index (BMI) showed less prefrontal activity when using the cognitive strategy to regulate food craving than children with lower BMI, suggesting that the areas of the brain involved in regulating craving may differ depending on body mass.
“These results suggest that children experience stronger craving than adults but can also effectively regulate craving. Moreover, the mechanisms underlying regulation may differ for heavy and lean children,” the team said.
"Having this basic knowledge in hand is critical if we want to understand how our relationship with food changes across the lifespan," Silvers added.