Trying to Get Pregnant? Eating Fast Food May Delay Conception, Study Says

To get pregnant quicker, avoid the drive-thru and reach for fruit. That’s what findings from a study published in May 2018 in the journal Human Reproduction suggested, and researchers say the notion supports prior studies that show diet choices can impact fertility.

Unlike earlier studies‚ which primarily focused on couples who were already known to be infertile, the new research concentrates on women at a different stage of their pregnancy journey.

“Our work is different in that we recruited women in early pregnancy, and asked them about their pre-conception diet and how long they were trying to conceive. So the vast majority would normally have been considered to be fertile,” says Claire Roberts, a senior research fellow in pediatrics and reproductive health at The University of Adelaide in Australia.

Researchers defined infertility as taking more than a year to conceive, a definition that aligns with that of the Centers for Disease Control and Prevention (CDC). Of the 5,598 women included in the study, 340 of them previously had some type of assisted reproduction to help them get pregnant.

The study participants — who were 28 years old on average and recruited from Adelaide, Australia; Auckland, New Zealand; Cork, Ireland; and Leeds, London, and Manchester in the United Kingdom — were asked at about 15 weeks pregnant to recall foods they ate in the month prior to conception. More specifically, they were asked about how fruit, green leafy vegetables, fish, and fast foods featured in their diet.

Women who ate more fast food and less fruit took at least two weeks longer to become pregnant, according to the published findings.

As many of us can attest to, remembering what we ate last week, or even for breakfast this morning, isn’t the easiest task. Even if you do remember, we aren’t always honest with our doctors about our bad health habits, such as our junk food intake and how much alcohol we really drink. And the authors are clear to point out this is a major limitation of their work.

“Regarding whether women answered truthfully, it is likely that our data, particularly on fast food, is an underestimate of the amount women eat, as it would be reasonable to expect that women might admit to eating less fast food than they actually did consume,” Roberts says.

Additionally, not including more information from the male partners could have impacted the findings, which the authors acknowledged in their paper.

“They did not have information on the partners, which I think would have also been good information because obviously diet can impact sperm,” says Lynn Westphal, MD, director of fertility preservation and third party reproduction at Stanford Children’s Health in California, who was not involved in the study.

Aside from dietary habits, other bits of male partner information could have also made the study stronger, says reproductive specialist Wendy Chang, MD, partner and scientific director of Southern California Reproductive Center, who also was not involved in the study.

“I think having male fertility, male alcohol intake, male habits, like tobacco or marijuana or other chemical exposures — that can clear up some of the confounding factors, too,” Dr. Chang says. According to the CDC, risk factors for infertility in men include smoking, drinking too much alcohol, using marijuana, and being overweight or obese. In women, excess alcohol use, smoking, and extreme weight loss and gain are also risk factors for infertility, the CDC notes.

Although the study findings suggest that whole foods may help improve fertility, Roberts is interested in exploring whether a good-quality diet is necessary or if supplements can do the same. But that calls for another study, considering the current one didn’t look at the effect of supplementation.

Regardless of whether you’re trying to get pregnant, it’s well documented that a good diet is critical for overall health. But for mothers expecting — either now or in the future — it’s especially important, the research shows.

“Women who are thinking about conceiving should start having as healthy as a diet as they can before they get pregnant,” Dr. Westphal says. “We know that very early prenatal environment is so key to the long-term health of that child, and a lot of people don’t realize how their health can affect the health of their children.”