Image Credit: Joe Raedle / Staff / Getty Images 
Eating a diet heavy in ultraprocessed foods for just three weeks caused alarming weight gain and fertility decline in men, a new study reveals.
The new research shows that food processing, independent of calorie intake, has a significant effect on weight gain, fertility and metabolic health.
Forty-three men aged 20-35 were fed different diets, including a whole-food diet and a diet with significant quantities of ultraprocessed foods (around 75%, similar to typical American consumption patterns).
The men who were fed ultraprocessed foods gained significantly more weight than the men eating whole foods.
Even with similar calorie intake, men eating ultraprocessed foods gained more weight.
Men eating the ultraprocessed foods showed decreased levels of follicle-stimulating hormone, which drives sperm production. Sperm motility—a measure of how well sperm move—also decreased.
The fertility effects mirror a broader global trend observed between ultraprocessed food consumption and reproductive health. As the study notes, “concurrent with the rise in UPF consumption, semen quality has declined globally, with sperm count falling by approximately 60% since the 1970s.”
There were also worrying changes to metabolic patterns in the group eating ultraprocessed foods.
“We were shocked by how many body functions were disrupted by ultra-processed foods, even in healthy young men,” says the study’s senior author Professor Romain Barrès in a statement.
“The long-term implications are alarming and highlight the need to revise nutritional guidelines to better protect against chronic disease.”
If you’d like to know more about processed foods and why they’re so bad for your health, read our detailed primer on the subject here.
