Researching the link between ultra-processed diets and testosterone levels.
Key takeaways of Diet and Testosterone Study
- The ultra-processed diet led to 1.41 kg (3.10 lb) more body weight in the adequate-calorie arm and 1.28 kg (2.82 lb) more in the excess-calorie arm than the unprocessed diet. Research has also begun to explore the links between diet and testosterone, which may further impact overall health.
- Fat mass was about 1.00 kg (2.20 lb) and 0.96 kg (2.12 lb) higher after the ultra-processed diet in the adequate- and excess-calorie arms, respectively.
- Testosterone was 2.11 nmol/L lower in the adequate-calorie arm after the ultra-processed diet, but this difference was not statistically significant after adjustment.
- This study does not prove that ultra-processed foods cause low testosterone or infertility.
Diet and Testosterone: What a New UPF Study Found
When men think about improving testosterone, they often focus on resistance exercise, sleep, body composition, and testosterone boosters. Those factors matter. However, diet deserves attention too—not because specific foods have been proven to boost testosterone. Instead, dietary patterns may affect the metabolic and reproductive environment. This environment supports hormone health.
A new randomized trial found that a diet high in ultra-processed foods led to greater fat gain and less favorable changes in selected cardiometabolic and reproductive health markers than a less-processed diet, even when prescribed calories and macronutrient intake were matched (Preston et al., 2025).
Can diet and testosterone be connected?
Diet and testosterone may be connected, but this study does not prove that ultra-processed foods directly lower testosterone. It found that a three-week ultra-processed diet produced less favorable changes in fat mass, blood lipids, blood pressure, and selected reproductive markers. These effects were compared to those from an unprocessed diet.
In a study published in Cell Metabolism, Jessica M. Preston and colleagues (2025) examined whether food processing level could affect metabolic and reproductive health. Notably, the study looked at healthy young men.
That matters because many men approach testosterone as a supplement problem. Training quality, sleep, adequate energy intake, and body composition remain important considerations. However, this study suggests that the overall quality and processing level of your diet may also matter.
How the study was designed
The researchers enrolled 43 healthy men aged 20–35 years in a randomized, controlled, dual-arm 2 x 2 crossover dietary intervention (Preston et al., 2025).
Participants were assigned to either an adequate-calorie arm (n = 21) or an excess-calorie arm (n = 22), with the excess-calorie group receiving an estimated 500 kcal/day above energy needs. Within each arm, participants completed both diets for three weeks, separated by a 12-week washout period.
The diets were matched for calories, macronutrients, and meal contribution:
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Unprocessed diet: 66% of calories from unprocessed foods and less than 1% from ultra-processed foods.
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Ultra-processed diet: 77% of calories from ultra-processed foods and 5.5% from unprocessed foods.
The ultra-processed diet also contained more saturated fat, cholesterol, refined grains, added sugars, and dairy products, while providing less fiber (Preston et al., 2025).
The ultra-processed diet increased weight and fat mass
Compared with the unprocessed diet, the ultra-processed diet increased body weight by 1.41 kg (3.10 lb) in the adequate-calorie arm and 1.28 kg (2.82 lb) in the excess-calorie arm.
The difference appeared to be largely explained by fat mass:
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Adequate-calorie arm: 0.998 kg (2.20 lb) more fat mass.
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Excess-calorie arm: 0.956 kg (2.11 lb) more fat mass.
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Lean mass did not significantly differ between diets.
In the adequate-calorie arm, the ultra-processed diet also increased total cholesterol by 0.54 mmol/L and the LDL:HDL ratio by 0.39. In the excess-calorie arm, diastolic blood pressure was 4.83 mmHg higher after the ultra-processed diet (Preston et al., 2025).
What happened to testosterone and reproductive markers?
The testosterone result needs careful interpretation. In the adequate-calorie arm, testosterone was 2.11 nmol/L lower after the ultra-processed diet than after the unprocessed diet, but the adjusted result was not statistically significant.
That means the study found a concerning numerical trend, not conclusive evidence that ultra-processed foods reduce testosterone.
FSH, a hormone involved in sperm production, was 0.52 IU/L lower in the excess-calorie arm after the ultra-processed diet (p = 0.027) (Preston et al., 2025). Total sperm motility was 13.23 percentage points lower in the excess-calorie arm, but this finding was not statistically significant after adjustment (p = 0.162).
Sperm concentration and morphology did not significantly differ between diets.
Practical application for lifters
This study does not support obsessing over individual testosterone foods. It supports building your regular diet around foods that are minimally processed and nutrient-dense.
For most lifters, that means:
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Base most meals around minimally processed protein sources. Meat, fish, eggs, dairy, legumes, and other straightforward protein staples can cover much of your intake.
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Include carbohydrate sources with fiber. Fruit, potatoes, rice, oats, beans, and whole grains can support training performance and overall diet quality.
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Use ultra-processed foods as additions, not the foundation. The trial compared dietary patterns with dramatically different levels of ultra-processed foods; it did not establish that every packaged food is harmful.
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Focus on the big picture. Consistent training, adequate sleep, sensible calorie intake, and a mostly minimally processed diet are more productive priorities than chasing a single hormone hack.
Limitations
This was a randomized crossover trial, which is a strong design for comparing short-term dietary effects. Still, each diet period lasted only three weeks, so the study cannot tell us whether these outcomes persist, worsen, or normalize over months or years.
The study would include only healthy men aged 20–35 years with semen quality above World Health Organization lower reference values. The findings may not apply to older men, men with obesity, men with infertility, or men with clinically low testosterone.
Finally, the outcomes reported in this paper were exploratory secondary outcomes. The trial’s registered primary outcome—sperm DNA methylation—was not reported in this publication (Preston et al., 2025).
The bottom line on diet and testosterone
This study does not prove that ultra-processed foods cause low testosterone. It does show that over three weeks, an ultra-processed diet led to greater fat gain and less favorable changes in several cardiometabolic and reproductive health markers than an unprocessed diet.
For men interested in diet and testosterone, the practical takeaway is simple: keep training hard, sleep enough, and make minimally processed foods the base of your regular diet.
FAQ
Can ultra-processed foods lower testosterone?
Diet and testosterone may be linked, but this trial found no statistically significant reduction. While the adequate-calorie group showed a numerical drop of 2.11 nmol/L, the adjusted results were not definitive.
What foods support testosterone health?
Healthy testosterone levels rely on overall patterns like sufficient calories, protein, fiber, and minimally processed foods. This study did not evaluate individual “testosterone-boosting” foods.
Is all processed food bad for testosterone?
Complete elimination of processed food is likely unnecessary for testosterone health. This study compared extreme dietary differences (1% vs. 77% ultra-processed) but failed to establish a specific harm threshold.
References
Preston, J. M., Iversen, J., Hufnagel, A., Hjort, L., Taylor, J., Sanchez, C., George, V., Hansen, A. N., Ängquist, L., Hermann, S., Craig, J. M., Torekov, S., Lindh, C., Hougaard, K. S., Nóbrega, M. A., Simpson, S. J., & Barrès, R. (2025). Effect of ultra-processed food consumption on male reproductive and metabolic health. Cell Metabolism, 37, 1950–1960. https://doi.org/10.1016/j.cmet.2025.08.004
Medical Disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice. Consult a qualified healthcare provider before making changes to your diet, supplementation, or training program.
About the Author
Robbie Durand
Robbie Durand is an exercise physiologist and science writer specializing in evidence-based fitness and nutrition research. With over 15 years of experience translating peer-reviewed studies into actionable advice, Robbie helps readers make informed decisions about training, supplementation, and body composition.
