Children who choose to snack on chocolate more often than fruit could be under the influence of a gene that triggers pleasure, according to a study published in the journal Appetite.
Researchers found that a particular gene variation made some children eat more junk food than others. (Image: Shutterstock)
Michael Meaney, a McGill Professor of Medicine and a Senior Fellow in the Child & Brain Development program, studied eating choices and childhood obesity with his colleagues Patricia Silveira and Robert Levitan at the University of Toronto.
They found that children who carried a particular gene variation involved with dopamine signals, which is tied to obesity in adults, were more likely to choose unhealthy food. For the girls, the amount of junk food eaten during the study predicted body weight two years later.
“What the gene is doing is to basically point you in the direction of seeking out pleasurable stimuli associated with food,” Meaney says.
Through a larger research program, Meaney and his colleagues had followed these children from birth, testing, for example, their ability to control emotional impulses at the age of three. When the children were four years old, the researchers called them in again for cognitive testing — but the real test took place during snack time.
“On the table, laid out somewhat like a buffet, are little containers of foods, all of which are familiar to the children,” Meaney says.
The spread included healthy choices, such as apples, but also junk food such as potato chips and chocolate. Researchers told the children, who hadn’t eaten for at least two hours before the scheduled snack break, to eat whatever they liked for about 20 minutes.
“When we eat foods that are highly tasty and palatable, they’re pleasurable. But they’re more pleasurable for some people than for others,” Meaney says. “One of the things we found was the kids who were less able to emotionally regulate themselves were kids who were more likely to eat these particular types of foods.”
Meaney says the results also show how genes combine with factors such as environment and emotion to influence obesity.
“There is, I think, an emerging understanding that people who consume or over-consume foods that promote obesity are doing so not simply because they lack any kind of will-power,” he says.
These people use food to manage their mood, Meaney says, and in many cases their decisions are swayed by toxic stress.
“Stress is known to drive our appetite,” Meaney says. “That’s an understanding that is starting to yield benefits with respect to our ability to regulate obesity in adults, but it’s never been considered as a factor that might be at play with children as well.”
Obesity prevention campaigns often rely on teaching kids and their parents which foods are healthy. Meaney says they need to start addressing deeper issues such as stress and poverty.
“If we’re sitting around thinking, well how can we start to mitigate the risk of obesity in children, we should start by thinking about how to allow them to develop more constructive ways to deal with the stressors in their lives,” he says.