Regardless of the amount of calories ingested, an ultra-processed diet has deleterious effects, particularly on fertility and cardio-metabolic health in men, concludes a recent clinical study.
"The consumption of ultra-processed foods in itself, regardless of excessive calorie intake, is harmful to human health," shows this work published Thursday in the American journal Cell Metabolism and coordinated by Romain Barrès, researcher at the Institute of Molecular and Cellular Pharmacology of Sophia Antipolis (Inserm, CNRS and Côte d'Azur University), in France.
Globally, the consumption of ultra-processed foods has surged, and a growing number of epidemiological studies have pointed to its strong correlation, but not a direct cause-and-effect link, with a high risk of chronic diseases (obesity, diabetes, cardiovascular diseases, etc.), cancers, and mental disorders, emphasize the authors of the randomized study (with random distribution of participants).
Until now, only three clinical studies, following a process similar to drug evaluation, had sought to assess the direct effect of this diet on health and shown that it led to excess calorie consumption compared to a minimally processed diet.
For this new study, 43 healthy men aged 20 to 35, divided into two groups, followed two successive diets, with a three-month break in between: one rich in ultra-processed foods, the other based on minimally or unprocessed products, for three weeks.
One subgroup received both diets, identical in calories, in moderate quantities, adequate for their age, weight and level of physical activity, the other both diets in excess of calories of 500 kcal daily.
Blood tests, sperm analyses and other measurements (weight, cholesterol, etc.) were regular.
Among its notable findings, the study established an impact on fertility of the ultra-processed diet: a drop in sperm-stimulating hormone (FSH) and testosterone in most participants, and a decrease in the number of motile sperm.
Pollutants present in ultra-processed foods, which have endocrine-disrupting effects, could play a role, the researchers believe.
Another lesson: in three weeks, "the consumption of ultra-processed foods compared to that of unprocessed foods led to a weight gain of 1.4 kg and 1.3 kg respectively in the groups with adequate and excessive caloric intake", mainly in fat mass.
Individuals who reduced the level of processing in their diet notably lost weight.
The researchers acknowledge limitations to their study: because the participants were not hospitalized, their energy intake was measured based on their self-reports, and the short duration of the diets, three weeks, may have "induced acute responses," including an inflammatory level that could have stabilized over time.
Judging the term "ultra-processed" to lack a "clear and established definition," the National Association of Food Industries (ANIA) argued, among other things, in a press release "that there are no 'good' or 'bad' foods and that public health messages (...) should remain those concerning dietary balance, the notions of consumption frequencies and portions to achieve a varied and balanced diet."
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