Overeating During Pregnancy and Breastfeeding Changes the Child's Brain and Can Lead to Excessive Eating

Many expectant mothers feel cravings for certain foods during pregnancy and sometimes eat too much of it. However, research shows that this can have serious effects on the child’s health. According to a Rutgers study in Molecular Metabolism, children whose mothers are overweight during pregnancy and breastfeeding can become obese as adults because early overeating rewires the developing brain and increases cravings for unhealthy food.

Compulsive Eating by the Mother Can Cause the Child to Overeat Later

Researchers at Rutgers University in New Jersey followed this mother-to-child connection in mice in an experiment that began by allowing some mice to become obese during pregnancy and nursing on unlimited high-fat food, while others remained lean on unlimited healthy food. The experts found that mice born to obese mothers stay lean in adulthood if they eat unlimited healthy food, but eat more than mice born to lean mothers when given access to unhealthy food.

The results suggest that children whose mothers were overweight during pregnancy and breastfeeding may have difficulty moderating their consumption of unhealthy foods, but could safely eat their fill with healthy foods. The study could also help spark the development of brain-altering drugs that reduce cravings for unhealthy food.

Children born to overweight or obese mothers tend to be heavier in adulthood than those born to slim mothers. Experiments like this suggest that the explanation goes beyond environmental factors, such as learning unhealthy eating habits in childhood. Overeating during pregnancy and breastfeeding appears to rewire the brains of the developing child and possibly future generations.

Different Connections Between Two Parts of the Brain

In the experiment, the researchers gave three sister mice the high-fat food, and three other sisters got the healthy one. Once breastfeeding was complete, the researchers turned their attention to the 50 babies, who started out heavier or lighter in weight depending on their mother’s diet. Their weights evened out after all offspring were fed unlimited healthy food for several weeks, but it diverged again when researchers gave them constant access to a high-fat diet. All mice ate too much, but the offspring of overweight mothers ate significantly more than the others.

Further analysis showed that the different behaviors are likely due to different connections between two parts of the brain – the hypothalamus and the amygdala – that arose due to the mother’s different diets during pregnancy and breastfeeding.

The study provides mixed results. On the one hand, it suggests the possibility of staying lean while eating healthy until you’re full and avoiding junk food altogether. On the other hand, it shows that trying to eat moderate amounts of unhealthy meals can lead to overeating and obesity. Looking ahead, the study’s findings on dysfunctional brain circuits in the two groups of mice could help advance the development of drugs that block excessive cravings for unhealthy foods.

What Triggers Cravings During Pregnancy

So, according to research, the urge to eat unhealthy foods is problematic. However, each of us feels cravings from time to time. Especially during pregnancy the craving for certain foods is very high. During this period, the mother’s body goes through a series of changes to create a favorable environment for the development of the embryo. However, frequent consumption of tasty and high-calorie foods – resulting from cravings – contributes to weight gain and obesity during pregnancy, which in turn can negatively impact the baby’s health.

There are many myths and popular beliefs about this craving, although the neural mechanisms that cause cravings are not well understood. March Claret, lecturer at the Faculty of Medicine and Health Sciences at the University of Barcelona and leader of the Metabolism Group’s IDIBAPS Neuronal Control, together with researcher Roberta Haddad-Tóvolli, led a study published in the journal Nature Metabolism that provides new evidence of the changes in that neuronal activity that drive craving in an animal model.

Increase in Dopamine Levels Linked to Compulsive Eating

According to the results, the brains of female mice undergo changes during pregnancy in the functional connections of the brain’s reward circuits, gustatory and sensorimotor centers. In addition, just like pregnant women, female mice are more sensitive to sweet foods and binge-eat high-calorie foods. The change in these structures prompted the scientists to explore the mesolimbic pathway, one of the signaling pathways of dopaminergic neurons. Dopamine is an important neurotransmitter for motivational behavior. The team observed an increase in dopamine levels – and the activity of its receptor D2R – in the nucleus accumbens, a brain region involved in the reward circuit. This finding suggests that pregnancy induces a complete reorganization of the mesolimbic neuronal circuits through the D2R neurons. These neuronal cells—and their alteration—would be responsible for cravings, as the fear of food typical of pregnancy disappeared after their activity was blocked.

The team led by Claret and Haddad-Tóvolli showed that persistent food cravings have consequences for the offspring. They affect metabolism and the development of neural circuits that regulate food intake, leading to weight gain, anxiety and eating disorders. These results are shocking, according to the researchers, since many of the studies focus on analyzing how the mother’s enduring habits – such as obesity, malnutrition or chronic stress – affect the baby’s health. However, this study indicates that these brief but recurring behaviors, such as food cravings, are enough to put the child’s health at risk. The study’s conclusions could help to improve dietary guidelines for pregnant women to ensure adequate prenatal nutrition and prevent the development of diseases.