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Ultra-processed food: health risks even without excess calories.
The consumption of ultra-processed foods is associated with an increased risk of developing many chronic diseases. These effects are often considered to be linked to the excess calories associated with them. In an article published in Cell Metabolism Scientists show that effects on health and fertility can be observed regardless of calories consumed.
The epidemic of ultra-processed food
In France, approximately 801% of products available in supermarkets are so-called "ultra-processed" foods. They are characterized by industrial preparation processes and the addition of at least one synthetic ingredient.
For several years, epidemiological studies have established a strong correlation between their consumption and the onset of chronic diseases such as obesity, diabetes, and certain cardiovascular conditions. However, these studies reveal a correlation, not formal causality: they show a significant association without demonstrating that these foods are the direct cause of these pathologies.
Health and hormonal imbalance
To date, only three clinical studies have evaluated the direct effect of consuming ultra-processed foods on health. These studies focused primarily on metabolism and showed that a diet high in ultra-processed foods, offered without limit, led to overconsumption of calories compared to a minimally processed diet. This overconsumption made it difficult to distinguish the effects related to the nature of the foods from those related to excess calories.
In a study published in the journal Cell Metabolism, Scientists have shed new light on the subject. Approximately forty young men followed two successive diets: one rich in ultra-processed foods, the other based on minimally processed or unprocessed products. Two subgroups were formed; one receiving both diets in moderate quantities, appropriate for their age, weight, and level of physical activity, and the other receiving both diets with a 500 kcal excess per day. In each group, the quantity of calories from the ultra-processed diet and the minimally processed diet was the same. This experimental protocol made it possible to separate the effect of calorie overconsumption from that of the diet itself.
The results are concerning: an ultra-processed diet, with the same calorie intake and consumed in moderation, led to weight gain, an increase in body mass, and an increase in the LDL/HDL ratio, an indicator of cardiovascular risk. Certain hormonal changes were also observed, such as a decrease in two hormones involved in metabolism and male fertility (GDF-15 and FSH, respectively). Sperm quality also tended to deteriorate, with a decrease in the number of motile sperm.
The endocrine disruptor angle
The complexity of industrial processes, the addition of additives, and the increased number of steps involved in preparing ultra-processed foods mechanically increase the risk of contamination by industrial pollutants. These substances could play a role in the harmful effects of ultra-processed foods on health. In this study, measuring pollutants and pesticides in the blood and seminal fluid of participants revealed changes in blood lithium levels and in the levels of a plasticizer (cxMINP phthalate), an endocrine disruptor, which was found in higher quantities in the blood and seminal fluid after consuming an ultra-processed diet.
This study highlights the role of ultra-processed foods on the health of the male reproductive system, possibly through the action of endocrine disruptors. It establishes that the number of calories consumed is not the sole factor responsible for these detrimental effects and reinforces the idea that the ultra-processed nature of foods is a nutritional dimension in its own right.
Figure: Participants in the group receiving meals containing an adequate amount of calories relative to their energy needs (group Adequate calorie intake) or the group participants receiving meals containing 500 kcals more than their daily energy requirement (group Overconsumption of calories) have similar physiological responses to minimally and ultra-processed diets: In both groups, compared to the minimally processed diet, the ultra-processed diet is associated with lower levels of FSH (Follicle Stimulating Hormone) and testosterone, a lower sperm count, higher fat mass, a higher LDL/HDL ratio, less lithium and more phthalate in the blood and seminal fluid.
Learn more: Jessica M. Preston, Jo Iversen, Antonia Hufnagel, Line Hjort, Jodie Taylor, Clara Sanchez, Victoria George, Ann N. Hansen, Lars Ängquist, Susan Hermann, Jeffrey M. Craig, Signe Torekov, Christian Lindh, Karin S. Hougaard, Marcelo A. Nobrega, Stephen J. Simpson, and Romain Barrès. Effect of ultra-processed food consumption on male reproductive and metabolic health, Cell Metabolism (2025)
Link to the original article in the journal Cell Metabolism: https://doi.org/10.1016/j.cmet.2025.08.004
Link to the article published in the newspaper Le Figaro: The harmful impact of ultra-processed foods on weight and male fertility