The findings, of an animal study, showed that an unhealthy diet not only creates health problems for expectant mothers, but also alters childrens' development of the brain and endocrine system which may cause long-lasting mental health ramifications.
"Given the high level of dietary fat consumption and maternal obesity in developed nations, these findings have important implications for the mental health of future generations," said Elinor Sullivan, assistant professor at the Oregon Health and Science University (OHSU) in the US.
Further, exposure to a high-fat diet during gestation and early in development impaired the development of neurons containing serotonin -- a neurotransmitter that is critical in developing brains.
On the other hand, introducing the child to a healthy diet at an early age also failed to reverse the effect, the researchers said.
"It's not about blaming the mother," but "about educating pregnant women about the potential risks of a high-fat diet in pregnancy and empowering them and their families to make healthy choices by providing support. We also need to craft public policies that promote healthy lifestyles and diets," Sullivan noted.
For the study, published in the journal Frontiers in Endocrinology, the team tested the effect of a maternal high-fat diet on non-human primates, tightly controlling their diet in a way that would be impossible in a human population.
Researchers grouped a total of 65 female Japanese macaques into two groups, one given a high-fat diet and one a control diet during pregnancy.
They subsequently measured and compared anxiety-like behaviour among 135 offspring and found that both males and females exposed to a high-fat diet during pregnancy exhibited greater incidence of anxiety compared with those in the control group.