Ultra-Processed Foods May Harm Male Fertility, Study Finds

• Ultra-processed foods can increase the risk of multiple chronic health conditions, such as heart disease and type 2 diabetes.
• A new study found that a diet heavy in ultra-processed foods can harm male reproductive health and reduce sperm quality.
• The researchers say that ultra-processed foods may contain molecules found in plastics that are known to disrupt hormonal systems in the body.

A new study reports that ultra-processed foods may be linked to a decline in male reproductive health, including sperm quality.

The research, published on August 28 in Cell Metabolism, states that regular consumption of ultra-processed foods has several effects on a person’s health.

These include higher cholesterol levels and increased body weight. They noted that participants in their study gained more than a kilogram of weight when they ate ultra-processed foods. The amount of fat mass in their bodies also increased.

The researchers added that “sperm quality trended toward impairment” when participants were on an ultra-processed diet.

The researchers pointed out that these health effects occurred even when a person on an ultra-processed diet consumed the same number of calories as a person on another type of diet.

“This study provides evidence that consumption of ultra-processed food is detrimental for cardiometabolic and reproductive outcomes, regardless of excessive caloric intake,” the study authors wrote.

Philip Werthman, MD, a urologist and director of the Center for Male Reproductive Medicine and Vasectomy Reversal in Los Angeles, says the study is proof that what you eat can be more important than how much you eat.

“It’s not the calories you’re getting. It’s the type of calories you’re getting,” Werthman told Healthline.

For their study, researchers recruited 43 males ages 20–35. Each participant spent three weeks on both a diet primarily of ultra-processed foods and a diet of unprocessed foods, with a 3-month “washing out” period between the two diets.

Half of the participants started on the unprocessed diet while the other half began with the ultra-processed diet. Half of the men from each group were also put on a diet that included 500 extra calories per day.

Researchers noted that subjects on the ultra-processed diet experienced an increase in the phthalate cxMINP, a substance found in plastics that can disrupt hormones.

Those on the ultra-processed diet also saw decreases in their testosterone levels and follicle-stimulating hormones, which are crucial for sperm production.

The researchers said some of the endocrine-disrupting substances may come from the plastic packaging used for ultra-processed foods.

They note that the introduction of ultra-processed foods in the 1970s seems to fall in line with a 60% decline worldwide in sperm count.

Kristin Kirkpatrick, president of KAK Consulting and a dietitian at Cleveland Clinic’s Department of Wellness & Preventive Medicine, said the research sends a clear message.

“The study found that endocrine disrupters and other components altered hormone levels in men, even if the men were healthy,” she told Healthline. “This means, even if you’re healthy based on other parameters, yet consume a diet higher in ultra-processed foods, you still are at risk for increases in chronic conditions.”

Werthman added that a man’s general health can also affect their reproductive system. For example, a person who has gained weight, developed type 2 diabetes, or experienced a rise in cholesterol levels may see a decline in reproductive health measures such as sperm quality.

“The reproductive system is a function of your overall health,” Werthman explained. “The reproductive system is quite sensitive.”

Michael Eisenberg, MD, a professor of urology at Stanford University, had one caution about the study’s conclusions.

“While none reached statistical significance, there does appear to be a decline in semen quality when examining the summative data,” he told Healthline. “However, it’s important to note that the intervention was for three weeks, and a cycle of sperm production typically takes between two to three months.”

The Centers for Disease Control and Prevention (CDC) reports that ultra-processed foods account for an average of 55% of total calories consumed by people in the United States.

It notes that people under 19 years of age tend to eat slightly more ultra-processed foods than adults 19 years and older. The agency states there is little difference in ultra-processed food consumption between men and women.

The CDC says ultra-processed foods tend to be “hyperpalatable, energy-dense, low in dietary fiber, and contain little or no whole foods, while having high amounts of salt, sweeteners, and unhealthy fats.”

It states that sandwiches (including burgers), sweet bakery products, sweetened beverages, and savory snacks are among the top sources of calories from ultra-processed foods.

An April 2025 study estimated that ultra-processed foods were linked to 124,000 preventable deaths in the United States during a two-year period.

Kirkpatrick said there are a number of reasons for these impacts, including what a person is not eating.

“Consuming ultra-processed foods means that other foods, which are found to help in the prevention of heart disease (like fresh fruit and vegetables, healthy fats, and fiber) are not being consumed,” she said.

“Further, excess sugar and sodium consumption has been found in multiple studies to pose a significant risk to heart health. Sugar and sodium are common ingredients in ultra-processed foods.”

Werthman said the pattern is clear. “This study is another confirmation that the food industry has been poisoning us for the past 20 to 30 years,” he noted. “We see the effects of that now.”

Experts say there are lifestyle habits that can help improve and maintain male reproductive health.

“In general, good diet (whole grains, fruits, vegetables), exercise, and maintaining a good body weight will help overall and reproductive health,” said Eisenberg.

Werthman says a healthy diet is “a big component” of that equation, but noted that men, especially those in the process of trying to have children, should exercise regularly as well as avoid alcohol and tobacco.

Werthman noted that heat sources such as saunas and hot tubs can temporarily impact sperm quality and quantity.

“All these things affect the reproductive system,” he said. “The body is an integrated system.”