Women who are overweight during pregnancy aren’t any more likely to have children who suffer with obesity during their lives than normal-weight, according to a surprising new study.
But eating well during pregnancy is a key factor in a baby’s obesity risk, regardless of how much weight an expectant mother carries or gains, according to researchers from Baylor College of Medicine in Houston.
The study — detailed in the FASEB Journal, published by the Federation of the American Societies for Experimental Biology — suggests that excess fat calories consumed in pregnancy can alter the genes in unborn babies in a way that raises the likelihood that they will be overweight or obese throughout their lifetimes.
"We are finding that the cycle of obesity likely begins in the womb, however, we are also finding that obesity does not necessarily beget obesity," said Dr. Kjersti M. Aagaard, with the Division of Maternal-Fetal Medicine and the Department of Obstetrics and Gynecology at Baylor College.
"A diet laden with fat changes the molecular machinery which chemically modifies the structure of the developing infant's genetic material….which in turn, alters key regulators of fat and glucose metabolism in the infant. It is our hope that these early steps will in turn break the cycle of obesity in the generations to come."
The findings are based on tests on three groups of pregnant primates. The first ate a healthy pregnancy diet (13 percent fat); the second consumed a high-fat diet (35 percent fat); and the third ate a high-fat diet for several years, became obese, and was then was put on a healthy diet.
Researchers found those on a healthy diet had infants who were less likely to be obese or overweight than those fed an unhealthy high fat diet — regardless of weight during pregnancy.
"Even if a woman isn't eating well before pregnancy, adopting good eating habits during pregnancy is still very good for the child and for her,” said Dr. Gerald Weissmann, editor of The FASEB Journal. “This new report shows how diet affects offspring at the molecular level and points to new treatments for overweight people who were not fortunate enough to have mothers who ate well during pregnancy."