Eating a lot of processed foods may lower two important hormones—one that helps control appetite and another that helps make sperm—which could hurt both your metabolism and fertility.
Scientific Claim
Consumption of ultra-processed food is associated with reduced levels of growth/differentiation factor 15 (GDF15) and follicle-stimulating hormone (FSH), indicating potential disruption of energy metabolism and sperm production in adult men.
Original Statement
“Several hormones involved in energy metabolism and spermatogenesis were affected, including decreased levels of growth/differentiation factor 15 and follicle-stimulating hormone.”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design cannot support claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The abstract reports hormone changes but does not confirm randomization or control for confounders. Causal language is inappropriate; only association is supported.
More Accurate Statement
“Consumption of ultra-processed food is associated with reduced levels of growth/differentiation factor 15 (GDF15) and follicle-stimulating hormone (FSH), suggesting a potential disruption of energy metabolism and sperm production in adult men.”
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Randomized Controlled TrialLevel 1bIn EvidenceWhether ultra-processed food intake directly suppresses GDF15 and FSH levels in men under controlled dietary conditions.
Whether ultra-processed food intake directly suppresses GDF15 and FSH levels in men under controlled dietary conditions.
What This Would Prove
Whether ultra-processed food intake directly suppresses GDF15 and FSH levels in men under controlled dietary conditions.
Ideal Study Design
A double-blind, crossover RCT of 50 healthy men aged 25–40, randomized to 4 weeks of ultra-processed diet vs. unprocessed diet (matched for calories, protein, fat, fiber), with serial blood draws to measure GDF15 and FSH at baseline, mid-intervention, and endpoint, controlling for sleep, stress, and physical activity.
Limitation: Short-term; may not reflect chronic hormonal adaptation.
Prospective Cohort StudyLevel 2bWhether habitual ultra-processed food intake predicts long-term declines in GDF15 and FSH in men.
Whether habitual ultra-processed food intake predicts long-term declines in GDF15 and FSH in men.
What This Would Prove
Whether habitual ultra-processed food intake predicts long-term declines in GDF15 and FSH in men.
Ideal Study Design
A prospective cohort of 10,000 men aged 30–50 followed for 8 years, with annual dietary assessments and serum measurements of GDF15 and FSH, adjusting for BMI, smoking, alcohol, and testosterone levels.
Limitation: Cannot establish directionality or rule out reverse causation (e.g., low hormones leading to poor diet).
Case-Control StudyLevel 3bWhether men with low FSH or GDF15 levels have higher ultra-processed food intake compared to healthy controls.
Whether men with low FSH or GDF15 levels have higher ultra-processed food intake compared to healthy controls.
What This Would Prove
Whether men with low FSH or GDF15 levels have higher ultra-processed food intake compared to healthy controls.
Ideal Study Design
A case-control study comparing 200 men with clinically low FSH (<2.5 IU/L) or GDF15 (<500 pg/mL) to 200 age-matched controls, using validated food frequency questionnaires to assess ultra-processed food intake over the prior year.
Limitation: Retrospective design prone to recall bias and confounding.
Evidence from Studies
Supporting (1)
Effect of ultra-processed food consumption on male reproductive and metabolic health.
This study gave men either ultra-processed or unprocessed food and found that the ultra-processed diet lowered two key hormones (GDF15 and FSH) linked to energy and sperm production — exactly what the claim says.