Pregnant Women Who Eat American Diet Are More Likely to Have Obese Children


You are what you eat, or so the saying goes.

And apparently so is your baby. Perhaps for life.

Research published recently in American Journal of Physiology showed that when rats were fed the typical diet consumed by American mothers, their offspring more likely wound up obese, even if the mothers themselves were not obese.

In a news release, lead author Eric Zorrilla of The Scripps Research Institute in San Diego explained that the experiment involved two sets of rats. One group had been bred to be “obesity resistant” and the other bred to be particularly vulnerable to obesity.

The mothers ate the “typical Western diet” before, during and after pregnancy (during breastfeeding). Regardless of mom’s genetics, their offspring ended up obese.

Trademarks of the Western diet include red meats, refined sugars and saturated fats, while fresh fruits and vegetables are less common.

Related: Does Red Meat Harm Your Heart as Much as You Think?

“Your diet itself matters, not just whether you are gaining excess weight or developing gestational diabetes,” Zorrilla explained.

The researchers found that as the rats entered adolescence and were on a diet of standard rat chow, some weight disappeared during periods of growth. “Although body weight normalized with chow feeding during adolescence, young adult Western diet offspring subsequently showed decreased energy expenditure and, in DR offspring, decreased lipid utilization as a fuel substrate,” the authors wrote in the paper. “By mid-adulthood, maternal Western diet DR offspring ate more chow, weighed more, and were fatter than controls. Thus, maternal Western diet covertly programmed increased adiposity in childhood and adulthood, disrupted relations of energy regulatory hormones with body fat, and decreased energy expenditure in offspring of lean, genetically obesity-resistant mothers. Maternal Western diet exposure alone, without maternal obesity or overnutrition, can promote offspring weight gain.”

Per the Scripps news release, the Western diet seemed to activate a “program” that resulted in a slower metabolism for the baby rat’s life. Only during adolescence did the extra pounds briefly come off the rats. “What we found interesting was that sometimes you see the same thing in humans, when a kid goes through a growth spurt,” first author Jen Frihauf of Scripps.

The researchers also found that the mother rats especially vulnerable to obesity had a more difficult time becoming pregnant, and had smaller litters. “This wasn’t the focus of the study, but it supports the idea that a Western diet promotes infertility in mothers vulnerable to diet-induced obesity,” said Zorrilla.

Related: Eat These Foods Instead of Meat to Help You Feel Full

The takeaway? Even mothers who are not obese need to be schooled about proper nutrition before, during and after pregnancy. “Doctors often use weight gain as a hallmark of a healthy pregnancy, but we realized there was something going on in utero that wasn’t detectable in the mother’s weight,” Frihauf said.

Remarkably, studies have shown that even father’s diets can “control how genes are expressed” and “can affect obesity risk in offspring,” according to the news release. So, expectant fathers need to learn to eat healthy, too.