Ultra-Processed Foods Consumption May Affect Male Reproductive Health: Study

Researchers have found that diets high in ultra-processed foods may reduce male testosterone levels, which can dramatically affect sperm production.

A new study indicates that diets high in ultra-processed foods (UPF) can negatively affect men’s cardiometabolic and reproductive health, adding to the growing evidence about the long-term impact the widely consumed junk foods pose.

Ultra-processed foods are heavily manufactured products that contain various additives, like sugars, unhealthy fats and salt, which are designed to enhance flavor, extend shelf life, or improve texture without providing any nutritional value. They include sugary drinks, packaged snacks, instant noodles and processed meats.

In findings published in the journal Cell Metabolism on August 28, researchers linked high UPF consumption to greater weight gain in men, and suggested that chemical contaminants commonly found in these foods may impair sperm quality and motility.

Researchers have previously linked frequent consumption of these kinds of foods to a number of other long-term health risks, including type-2 diabetes, non-alcoholic fatty liver disease (NAFLD) and other chronic illnesses, especially among children.

These concerns are particularly pressing given that over the past 50 years, rates of obesity and type 2 diabetes have soared while sperm quality has declined, prompting scientists to investigate whether ultra-processed foods may be driving these trends.

As a result of these studies, processed food lawsuits are being investigated against major manufacturers such as Kraft Heinz, Coca-Cola, General Mills and Kellogg’s, claiming these companies knew or should have known about UPFs’ adverse long-term health effects, yet refused to act due to a desire for profits over human health.

In the new study, a team of international researchers compared the health impact of unprocessed and ultra-processed diets on 43 men aged 20 to 35, with participants spending three weeks on each diet. 

Half of the men were given a high-calorie version of the diets with an extra 500 calories per day, while the other half received a version with calories tailored to their size, age and activity level. Both the unprocessed and ultra-processed diets were matched for total calories, protein, carbohydrates and fats.

Led by Jessica M. Preston, the research team  found that the men gained about 1 kilogram more fat mass on the ultra-processed diet than on the unprocessed diet, regardless of whether they were on the normal- or high-calorie version.

The researchers also found that men on the ultra-processed diet showed higher levels of the hormone-disrupting chemical phthalate cxMINP, a substance used in plastics, along with lower levels of testosterone and follicle-stimulating hormone, both of which are essential for sperm production.

“Our results show that ultra-processed foods harm reproductive and metabolic health, even when not consumed in excess. This suggests that it is the processed nature of these foods that makes them harmful.”

— Jessica M. Preston, Effect of ultra-processed food consumption on male reproductive and metabolic health

Preston’s team concluded that regardless of caloric intake, ultra-processed foods harm human health. As a result, they recommend that individuals try to move away from a diet high in these kinds of products.

Ultra-Processed Foods Lawsuits

In December 2024, one of the first ultra-processed foods lawsuits was filed by Bryce Martinez against the food industry, alleging that products sold by major brands like Kraft Heinz, Coca-Cola and General Mills were aggressively marketed to children and low-income communities without proper warnings, despite known health risks, leading to Martinez’ childhood diabetes and NAFLD.

However, last month, a federal judge dismissed the lawsuit, ruling that the claims were overly broad and vague, lacking a clear legal basis or a specific link between the plaintiff’s injuries and any particular product, ingredient or brand. 

The decision is likely to affect how current and future plaintiffs pursue claims and structure lawsuits alleging that routine consumption of ultra-processed foods contributed to type 2 diabetes or NAFLD in themselves or their children.

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