New research suggests that a mother's diet during pregnancy and lactation may prime offspring for weight gain and obesity later in life.

Researchers at Penn State College of Medicine conducted a rat study and found that rats whose mothers consumed a high-fat diet had feeding controls and feelings of fullness that did not function normally.

Previous studies have shown that obesity compromises the neurocircuits that control how the stomach and intestine work to regulate how much people eat, and that the time around pregnancy and lactation is important in the development of these circuits. In both human and laboratory studies, the offspring of mothers who are obese or consume a high-fat diet during pregnancy have been shown to be much more likely to be overweight and have weight-related problems such as metabolic syndrome, diabetes and heart disease later in life.

In the new study, researchers fed one group of rats a high-fat diet during pregnancy and lactation. Their offspring were fed the same diet after weaning. When the rats reached adolescence, the researchers measured their neural activity involved in energy balance and appetite regulation.

"We looked at the circuits that relay information from the stomach and the small intestine to the brain and back to the stomach telling it how to work," said lead investigator Kirsteen Browning, associate professor of neural and behavioral sciences.

These normal reflex mechanisms, which help limit the amount of food we eat, can malfunction and become less sensitive in obesity.

"We found that parts of these reflexes were actually compromised even before we saw obesity," Browning said. "Rats on the high-fat diet looked exactly the same as the control group rats in terms of weight, but their feeding reflexes were already beginning to be compromised."

The findings suggest that there are significant effects of maternal and perinatal diet on some of the regions that control feeding and satiety in the brain. Exactly how maternal diet influences these functions is still unknown.

"It's time that we start to take seriously the idea that obesity is, in part, a brain disease," Browning said.

However, Browning emphasized that obesity is a complex disease with many genetic and environmental factors playing important roles.

The findings are detailed in the Journal of Physiology