Does Childhood Obesity Start Before Mom Gets Pregnant?

Whether it’s a few pounds or 100, for health reasons or fashion, most women -- whether they’ll tell you or not -- want to lose weight.

And new research from the University of Texas focusing on obesity and pregnancy may give women another motivation to slim down: if mom is at a healthy weight when she gets pregnant, her unborn baby will reap the benefits.  

UT Health Science Center San Antonio obstetrics researchers were curious; if mothers lose body fat before pregnancy, does it improve the lifelong health of their children?

Since babies born to obese mothers tend to be predisposed to obesity themselves, answering this question could be one way to break the transgenerational cycle and help end the obesity epidemic.

Before or after

The study, a collaborative effort between researchers with the Center for Pregnancy and Newborn Research at the Health Science Center and the National Institute of Nutrition in Mexico City, studied how weight effects female rats before mating.

Two groups of female rats were fed a high-fat diet so they would become obese. One group was put on a diet a month before mating while the other group kept eating the same high-fat food during pregnancy and while nursing their offspring.

At weaning, the researchers found triglycerides, leptin, insulin and insulin resistance were elevated in the babies of the obese mothers. The babies born to obese mothers also had an increase in fat mass and fat cell size.

However, in the offspring of the dieting mothers, triglycerides, leptin, insulin and insulin resistance were at normal levels. Any fat mass and fat cell size increases were reversed in this group, too, thanks to the dietary intervention.

Developmental progrmming

The authors said this is the first study showing adverse metabolic effects on future offspring can be reversed or avoided by moms adopting healthy diets before getting pregnant.

"Developmental programming sets the scene that influences one's health for the rest of life," Dr. Nathanielsz said.

Some differences however, such as heart disease and obesity, may not appear until much later in life.

Nathanielsz said one of the most notable findings of this study was the offspring of the obese mothers had high levels of leptin, the hormone that signals to the brain to decrease appetite.

"This may mean they've developed a brain that is resistant to the signals that tell them they're getting fat, and they just go on eating and thus get fat as their mothers were. That is what we mean when we say that the effects are transgenerational.“

Nathanielsz adds the leptin levels in offspring of the diet-intervention mothers were normal, showing the cycle of obesity in families can be broken.

The experiment was novel in developmental programming -- the first time a research team intervened to recuperate some animals from high-fat diets. Still, Nathanielsz said more research needs to be done regarding diet and pregnancy.

"We were able to see at least a 50 percent to 60 percent return," said Nathanielsz. "This is a first step.”