Individuals with mothers who were overweight during pregnancy and nursing may face a higher risk of adult obesity, as early overnutrition can reprogram their developing brains to desire unhealthy foods, according to a Molecular Metabolism study conducted by Rutgers researchers.
Rutgers researchers investigated the mother-to-child connection in mice by allowing some mice to become obese through unrestricted high-fat diets during pregnancy and breastfeeding, while others remained lean with unlimited access to healthy food. They discovered that offspring of obese mothers remained slim when provided unlimited healthy food as adults, but consumed significantly more unhealthy food than those born to lean mothers when given access to it.
The findings indicate that while people whose mothers were overweight during pregnancy and nursing may struggle to moderate their consumption of treats, they could safely eat their fill of healthy foods.
The study may also help inform the development of brain-altering drugs that reduce cravings for unhealthy food.
“People born to overweight or obese mothers tend to be heavier in adulthood than people born to leaner mothers, and experiments like this suggest that the explanation goes beyond environmental factors such as learning unhealthy eating habits in childhood,” said Mark Rossi, a professor of psychiatry at Rutgers Robert Wood Johnson Medical School and senior author of the study. “Overnutrition during pregnancy and nursing appears to rewire the brains of developing children and, possibly, future generations.”
In the experiment, researchers gave the high-fat food to three sister mice and the healthy chow to another three of their sisters. Once breastfeeding was complete, the researchers turned their attention to the nearly 50 pups — who predictably started at heavier or lighter weights, depending on their mom’s diet.
Their weights converged (at healthy levels) after all the pups received several weeks of unlimited healthy chow, but they diverged again when the researchers offered them constant access to the high-fat diet. All the mice overate, but the offspring of overweight mothers overate significantly more than the others.
Further analysis indicated that the differing behaviors probably stemmed from differing connections between two parts of the brain — the hypothalamus and the amygdala — that arose because of differing maternal nutrition during pregnancy and breastfeeding.
The study has mixed implications for people born to overweight mothers who struggle with their own weight. On the one hand, it suggests the possibility of staying lean while eating healthy food to satiety and avoiding junk entirely. On the other hand, it suggests that efforts to eat moderate quantities of unhealthy treats may spur overconsumption and obesity.
Looking forward, the study’s finding about disrupted brain circuits in the two groups of mice may help inform the creation of drugs that would block the excess desire to consume unhealthy foods.
“There’s still more work to do because we don’t yet fully understand how these changes are happening, even in mice,” Rossi said. “But each experiment tells us a little more, and each little bit we learn about the processes that drive overeating may uncover a strategy for potential therapies.”
Reference: “Maternal overnutrition is associated with altered synaptic input to lateral hypothalamic area” by Kuldeep Shrivastava, Thaarini Swaminathan, Alessandro Barlotta, Vikshar Athreya, Hassan Choudhry and Mark A. Rossi, 8 March 2023, Molecular Metabolism.