Eating a high-fat diet during pregnancy causes permanent changes in the fetal brain that can result in overeating and obesity early in life, according to a study with rats.

The researchers from Rockefeller University in New York City said their finding is an important advance in understanding mechanisms of fetal programming. It also sheds light on the production of new brain cells, helping to explain the dramatic rise of childhood obesity in the United States over the past three decades.

“We’ve shown that short-term exposure to a high-fat diet in utero produces permanent neurons in the fetal brain that later increase the appetite for fat,” study senior author Sarah F. Leibowitz, director of the Laboratory of Behavioral Neurobiology at Rockefeller, said in a university news release. “This work provides the first evidence for a fetal program that links high levels of fat circulating in the mother’s blood during pregnancy to the overeating and increased weight gain of offspring after weaning.”

For the study, pregnant rats were fed either a high-fat or a balanced diet for two weeks. Pups born to mothers that ate the high-fat diet ate more, weighed more throughout life, and began puberty earlier than pups born to mothers that ate a balanced diet. The pups born to the mothers that at the high-fat diet also had higher levels of triglycerides in the blood at birth and as adults, and also had greater production of brain peptides that stimulate eating and weight gain.

The study was published in the Nov. 12 issue of the Journal of Neuroscience.

The creation of neurons that increase the appetite for fat may also occur in human babies born to mothers who eat a high-fat diet during pregnancy, Leibowitz said.

“We’re programming our children to be fat,” she believes. “I think it’s very clear that there’s vulnerability in the developing brain, and we’ve identified the site of this action where new neurons are being born. We now need to understand how the lipids affect these precursor cells that form these fat-sensitive neurons that live with us throughout life.”

(Source: Rockefeller University, news release, Nov. 11, 2008)