How Your Pregnancy Diet Affects Your Baby's Fat Mass

A new study sheds some scary light on saturated fats. 

Pregnant Eating Pizza epicseurope/Shutterstock

Think if you eat a diet rich in fat during pregnancy it'll translate into a heavier baby? Maybe not—but a new study suggests that your child could have more fat tissue as a result of such a diet.

Researchers at the University of Colorado Denver Anschutz studied 1,040 mother-infant pairs to draw conclusions about the relationship between a mother's diet while expecting and her baby's body composition. They found that those moms-to-be who ate lots of saturated fats (eggs, dairy, meat) gave birth to babies with greater fat mass—regardless of their own body compositions before pregnancy. While the total number of calories consumed by a pregnant woman appears to have a larger effect on a baby's weight, saturated fat intake was closer linked to fat mass at birth, according to the study's lead author, Tessa Crume of the University of Colorado Denver Anschutz.

Related: Pregnancy Diet: 10 Rules To Eat By

The researchers checked in with the women involved in the study numerous times during their pregnancies, and asked them to report everything they had eaten during the past 24 hours each time. Then the researchers recorded the lengths, weights and head circumferences of the babies after birth.

Here's how dietary details broke down: Half the women surveyed were consuming up to 2,025 calories a day, while the other half consumed more. Researchers noted that for every 100-calorie-a-day increase in unsaturated fats (from things like olives, nuts, seeds) in a mom's diet, they observed about a six-gram increase in her newborn's fat mass. A 100-calorie-a-day increase in saturated fat (again, eggs, dairy, meat) was linked to a whopping 11-gram increase in the newborn's fat mass. 

But the researchers pointed out that while they found an association, this study could not prove that a mother's diet can affect her baby's composition—partly because the findings relied on self-reported details of the mother's eating habits. 

So, what does this mean for your pregnancy diet? Here's what Harvard University researcher Emily Oken, MD, who was not involved with the study, advised: Focus on eating a balanced diet full of healthy foods and don't take the saying 'eating for two' too seriously. “We are learning that healthy gain in early pregnancy is especially important–just a couple of pounds in the first trimester,” Dr. Oken said, according to Reuters“Women should aim to gain within the recommended amounts by continuing to exercise regularly and eating a nutrient-dense diet–avoid ‘empty’ calories such as those in sugary beverages, candy, and desserts.”