Ultra-Processed Foods Linked to Hormonal Disruption and Declining Sperm Quality in Men

A new study has found that ultra-processed foods can negatively impact men’s health in three critical ways: by promoting weight gain, disrupting natural hormone levels, and reducing sperm quality.

The research was led by scientists at the University of Copenhagen in Denmark. They examined whether the industrial processing of food could affect health. This was considered even when calories and nutrients were carefully matched.

While ultra-processed foods are already linked to obesity, cancer, and cardiovascular disease, this study highlights reproductive and hormonal risks. It raises new concerns for public health.

Study design and findings

The study involved 43 cisgender men aged 20 to 35 who followed two different diets separated by a three-month break. One diet consisted of 77 percent of calories from ultra-processed foods. The other diet relied mostly on unprocessed foods, making up 66 percent of calories.

Both diets were carefully matched for calories and nutrients, eliminating differences in energy intake or macronutrient composition. Despite this, men on the ultra-processed diet gained an average of one kilogram of body fat and showed increased levels of a phthalate compound called cxMINP, known to interfere with hormones.

Researchers also observed declines in testosterone and follicle-stimulating hormone, which are both essential for healthy sperm production and reproductive health.

Hormonal disruption and reproductive health risks

The findings add to growing evidence that ultra-processed foods have a direct impact on male reproductive health. Sperm quality has been declining worldwide over recent decades. Scientists have long suspected that changes in diet may be a contributing factor.

Lead researcher Romain Barrès, a molecular biologist at the University of Copenhagen, said the results were concerning.

“We were shocked by how many body functions were disrupted by ultra-processed foods, even in healthy young men. The long-term implications are alarming. They highlight the need to revise nutritional guidelines to better protect against chronic disease,” Barrès explained.

Why ultra-processed foods are different

Ultra-processed foods are defined not just by their industrial preparation but also by the inclusion of synthetic ingredients that can’t be found in a typical grocery store. They are designed for affordability, convenience, and enhanced flavor, offering longer shelf lives and mass appeal.

However, their widespread consumption has been linked to rising obesity rates, increased cancer risks, cognitive decline, and environmental harm.

Nutrition scientist Jessica Preston is also part of the research team. She emphasized that the risks exist even when UPFs are not consumed in excess. “Our results prove that ultra-processed foods harm our reproductive and metabolic health, even if they’re not eaten in excess. This indicates that it is the processed nature of these foods that makes them harmful,” Preston said.

Broader health and environmental concerns

While the study involved a relatively small sample size and only male participants, its controlled design strengthens the evidence that processing itself—not just calorie content—plays a harmful role. Previous research has suggested that additives, packaging chemicals, and the breakdown of industrial materials in UPFs may contribute to hormone disruption and inflammation.

The growing reliance on these foods worldwide raises urgent questions not only about personal health but also about the sustainability of global food systems.

This study, published in Cell Metabolism, provides new insight into how ultra-processed foods undermine men’s health by driving weight gain, disrupting hormones, and lowering sperm quality. It underscores the importance of rethinking dietary guidelines and reducing reliance on heavily manufactured foods in favor of healthier, less processed alternatives.

For individuals, the findings offer a reminder that health risks from processed foods extend beyond calories, affecting reproductive function and long-term wellbeing.