Scientists have found that a particular gene in the brain's reward system is linked to childhood obesity and tasty food choices, particularly for girls.
Contrary to "blaming" obese individuals for making poor food choices, researchers suggest that obesity lies at the interface of three factors: genetic predispositions, environmental stress and emotional well-being.
These findings shed light on why some children may be predisposed to obesity, and could mark a critical step towards prevention and treatment.
"In broad terms, we are finding that obesity is a product of genetics, early development and circumstance," said researcher Michael Meaney of McGill University.
Researchers studied pregnant women, some of whom suffered from depression or lived in poverty, and followed their children from birth until the age of ten.
For the study, researchers tested 150 four-year old children by administering a snack test meal. The children were faced with healthy and non-healthy food choices.
Mothers also completed a questionnaire to address their child's normal food consumption and preferences.
"We found that a variation in a gene that regulates the activity of dopamine, a major neurotransmitter that regulates the individual's response to tasty food, predicted the amount of 'comfort' foods - highly palatable foods such as ice cream, candy or calorie-laden snacks - selected and eaten by the children," said Patricia Silveira of McGill University.
"This effect was especially important for girls who we found carried the genetic allele that decreases dopamine function," Silveira said.
"Most importantly, the amount of comfort food eaten during the snack test in the four-year-olds predicted the body weight of the girls at six years of age," said Meaney.
"Our research indicates that genetics and emotional well-being combine to drive consumption of foods that promote obesity. The next step is to identify vulnerable children, as there may be ways for prevention and counselling in early obesity stages," Meaney added.
The study was published in the journal Appetite.
