...
By Daniella Gray
Reporter
0
Share
Newsweek is a Trust Project member
See more of our trusted coverage when you search.Prefer Newsweek on Googleto see more of our trusted coverage when you search.
Eating ultra‑processed foods may harm male fertility and also lead to early embryo growth, a new study has suggested.
Researchers analyzed dietary habits and fertility outcomes in more than 800 women and 650 male partners in the Netherlands.
The team's analysis found clear, sex‑specific links: men who consumed more ultra‑processed foods were less likely to conceive quickly, while higher intake among women was linked to smaller embryos and reduced yolk sac size in early pregnancy.
Read More on Health
While the study did not examine individual foods, ultra‑processed foods—often abbreviated as UPFs—generally include packaged snacks, fizzy drinks, processed meats and ready‑to‑eat meals, which are often high in sugar, unhealthy fats and additives.
...
“Even though UPFs are so common in our diets, very little is known about their potential relationship with fertility outcomes, and early human development,” said paper author and developmental epidemiologist professor Romy Gaillard—of the Erasmus University Medical Center in Rotterdam, The Netherlands—in a statement.
The study assessed couples’ diets during the so-called periconception period—the months before and just after conception—using detailed food questionnaires.
On average, ultra‑processed foods made up about a quarter of daily food intake for both men and women. For men, higher consumption was associated with a lower chance of conceiving.
Men with the highest intake also had a significantly higher risk of "subfertility," which is defined as taking 12 months or longer to conceive, or needing fertility treatment to do so. These associations remained even after accounting for factors such as age, body mass index, smoking, alcohol use and their partner’s diet.
...
Researchers believe that the findings may be the linked to how diet affects sperm health. Previous studies have shown that ultra‑processed foods are associated with poorer sperm quality, including reduced motility, or the ability of the cells to swim.
Diets rich in UPFs may also increase oxidative stress and exposure to hormone‑disrupting chemicals which are found in some food packaging, both of which can interfere with male reproductive function. Among women, ultra‑processed food intake was not consistently associated with fertility itself.
However, higher consumption was linked to smaller "crown–rump length"—a key measure of embryo size—at seven weeks of pregnancy, as well as a smaller yolk sac, an early structure that provides nutrients to the developing embryo before the placenta is fully formed. These effects were strongest early in the first trimester and became less pronounced later on.
Gaillard said that it is still too early to know how long before trying to conceive men would need to change their diet for it to improve fertility. Their study is one of the first to link higher consumption of ultra‑processed foods with a slightly higher risk of fertility problems in men.
The effect they found was small and matters more at a population level, because so many people now eat a lot of ultra‑processed food.
Gaillard told Newsweek that men do not need to make drastic diet overhauls to support fertility—small, realistic changes can help reduce ultra‑processed food intake.
"For example, choosing whole grains over processed grains, choosing plain yoghurt over flavored yoghurt, or replacing an ultra-processed snack with fruits or vegetables as a snack," she said.
Making these changes together as a couple, Gaillard noted, may be easier and more sustainable.
"Indeed traditionally, preconception recommendations for a healthy lifestyle strongly focus on mothers-to-be [but] I think our study adds to the evidence that fathers-to-be should also be more strongly involved in preconception care."
“Our research shows that we should think more broadly about fertility and early pregnancy,” Gaillard added. "Our results highlight the need to pay more attention to male health in the preconception period, which has traditionally been overlooked.”
The researchers stress that more studies are needed to confirm the findings and to see whether cutting back on these foods actually causes improvements. They also noted that there were limitation in how ultra‑processed food intake was measured in the present study.
"As this is an observational study, our study shows associations, but cannot prove direct causal effects of UPF consumption on these early life outcomes, " Gaillard cautioned.
Gunter Kuhnle—a professor of nutrition and food science at University of Reading who was not involved in the study—said that fertility is an important but very sensitive topic and should therefore be handled accordingly.
"Given that the assessment of ultra-processed food intake has severe limitations, the conclusions of the study, and the recommendations, need to be interpreted carefully," he said. "A concern is that such result [might] cause distress and self-blame in people who have unsuccessfully tried to conceive—and that it is used to give advice to people trying to conceive."
Established advice—prioritising a balanced diet, regular exercise and avoiding smoking—remains far more strongly linked to fertility outcomes.
Do you have a tip on a health story that Newsweek should be covering? Do you have a question about UPFs? Let us know via health@newsweek.com.
Reference
Lin, C. H. X., Gaillard, R., Mulders, A. G. M. G. J., Jaddoe, V. W. V., & Schipper, M. C. (2026). Periconceptional ultra-processed food consumption in women and men, fertility, and early embryonic development. Human Reproduction. https://doi.org/10.1093/humrep/deag023
View 0 Comments
Submit Correction
View Editorial & AI Guidelines