How to stop craving junk food: don't eat it in adolescence or pregnancy

While some might argue there’s no good time to eat junk food, researchers have discovered that there are two crucial points in a person’s life when exposure to junk food has the biggest impact: in utero and during adolescence.

The findings follow on from earlier research showing that women who eat junk food while pregnant predispose their children to be addicted to a high fat, high sugar diet by the time they stop breastfeeding.

“Our research suggests that too much junk food consumed late in pregnancy for humans has the potential to be more harmful to the child than excess junk food early in the pregnancy,” said Dr Jessica Gugusheff, postdoctoral researcher in the University of Adelaide’s School of Agriculture, Food and Wine.

Eating a healthier diet in late pregnancy could reduce the negative effects of eating junk food earlier in the pregnancy, the researchers found.

“The second critical window is adolescence, and we’ve found differences between males and females. Our experiments showed that eating a healthy diet during adolescence could reverse the junk-food preference in males but not females,” Dr Gugusheff said.

Junk food consumption at these critical points can desensitise the normal reward system that is based on the opioid and dopamine signalling pathway. Those with less sensitive reward systems need more fat and sugar to get the same ‘high’ than those with sensitive systems.

The brain experiences its fastest growth at these two moments in development, so junk food consumption has the greatest effect on the signalling pathways at these times.

The researchers say their findings will enable healthcare providers to better inform pregnant women about the lasting effect their diets have on the development of their child’s food preferences.

“It will help mothers to make better, more informed decisions about their diet choices by narrowing down the window of when exposure to a bad diet is most harmful to the child,” said Dr Beverly Mühlhäusler, Senior Research Fellow with the university’s FOODplus Research Centre.

“It will also enable us to target dietary interventions to times in development when they will be most beneficial.”