Researchers report that over the past 50 years, human sperm counts appear to have declined by more than 50% worldwide. And ultra-processed foods? They now account for more than half of total calorie intake in countries like the UK, USA, Canada, and Australia.
Do these two trends prove a direct cause? Not exactly. But they do raise important questions about what today’s modern diet may mean for the systems that help regulate our hormones, metabolism, and long-term well-being.
A new study is adding to this discussion by showing how quickly an ultra-processed diet can shift markers tied to male reproductive health. So let’s look at what the researchers found, and why food quality may matter more than we think.
Ultra-Processed Food and the Male Fertility Crisis: Is There a Connection?
In a 2025 study, researchers compared two diets for three weeks. One group followed an unprocessed diet full of whole foods. The other ate mostly ultra-processed foods (UPFs), which are described as industrially processed foods made from “highly transformed, derived, or synthesized ingredients.”
Both diets were matched for calories and macronutrients. That meant any differences in the outcomes reflected food quality rather than total energy intake. The researchers then noticed several clear patterns between the two groups:
Metabolic Changes
Participants on the ultra-processed diet gained about 2.2 pounds of fat during the three-week period.
They also showed higher triglycerides, higher levels of thyroid-related hormones (T3 and TSH), and shifts in cholesterol markers compared with the unprocessed diet group.
These changes appeared even without overeating.
Reproductive Markers
Reproductive markers also varied during the study. Compared with the unprocessed menu, the UPF diet was associated with a roughly 11% decline in testosterone, a ~14% drop in FSH, and an ~18% decrease in sperm motility.
These shifts happened over just a few weeks, highlighting how sensitive reproductive markers can be to differences in our diet.
Chemical Exposure
Blood and semen samples from the ultra-processed diet group showed higher levels of phthalates, chemicals commonly found in plastics and certain types of packaging.
So when two diets deliver the same calories and macronutrients yet produce such different outcomes, something else is in play. This study hints that maybe we need to think beyond what’s on the nutrition label when it comes to our health.
Processing Is More Than a Convenience Factor
We tend to think of processing as a shortcut. A way to make food faster, tastier, or something that can sit in a pantry for months without changing. But processing does more than extend shelf life. It reshapes food itself.
As ingredients are broken apart, reassembled, flavored, thickened, and packaged, the final product becomes something very different from what it started as. And in the study, those differences seemed to matter.
Here are a few reasons researchers think processing may play a role:
Refined Ingredients Lose Too Much
The structure of whole foods, including their fiber, fats, and proteins, gets lost as ingredients become isolates, sugars, and starches during processing.
That structure affects how filling a food feels, how long it takes to break down, and how its nutrients show up in the bloodstream. When that structure disappears, your body encounters those nutrients in a very different way.
Researchers note that these shifts in nutrient delivery sometimes track with broader metabolic patterns. This offers helpful context for why the two diets in the study produced such different results, even when the numbers on paper were the same.
What’s Missing vs. What’s Added
As UPFs lose the natural complexity of whole foods, sugar, emulsifiers, and preservatives get added back. And researchers have been exploring how these may interact with the gut environment.
New studies link specific additives with shifts in microbial activity and even raise questions about whether these changes correlate with hormone-related pathways. The science is still early, but it helps frame why processing may matter beyond nutrients alone.
Packaging and Chemical Exposure
Another layer of the study that caught attention? The rise in phthalates among participants eating the ultra-processed diet. These chemicals often come from plastics and packaging materials, and they can make their way into food during processing, storage, or handling.
Phthalates have been studied extensively, and many researchers consider them endocrine-disrupting chemicals. While the science is still evolving, and researchers in this study didn’t pinpoint a single source, eating a diet built largely around UPFs increased exposure to chemicals that rarely appear in whole-food eating patterns.
It’s one more reminder that our food landscape includes factors beyond ingredients alone.
Fertility: A Window Into Overall Strain?
Reproductive markers are sensitive. They tend to reflect the body’s broader environment, not just isolated factors. So when testosterone, FSH, or sperm motility shift over a short period, it may signal that larger systems are under some kind of metabolic or environmental pressure.
This does not mean ultra-processed foods directly cause fertility issues. But it does provide an interesting lens for understanding modern dietary patterns since reproductive markers often show changes earlier than other systems do.
Practical Ways to Shift Toward Real Food
Even small steps toward more whole or minimally processed foods can help create a baseline that feels less reliant on processing shortcuts.
Use “Convenience” Whole Foods
Minimally processed foods are not the enemy. Frozen fruits and vegetables, pre-washed greens, and pre-cut produce save time and make whole-food eating easier. If buying these means you’ll actually eat them, that counts as a win.
Give Yourself Daily Food Goals
Simple, repeatable goals like these help build momentum without overwhelm:
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Start the day with a protein shake.
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Add one extra serving of vegetables to lunch.
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Include a fermented food like plain yogurt, sauerkraut, or kimchi.
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Swap one processed snack for a whole-food option such as an apple or berries.
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Try to give one guilty pleasure a whole-food upgrade (like these Protein Peanut Butter Cups).
These habits shift your focus to nutrient density and naturally crowd out UPFs.
Embrace the Half and Half
If you’re not ready to ditch your favorite snack, split the portion and pair the rest with a whole-food choice. Over time, this gentle swap can make that go-to treat feel less automatic.
Think in terms of consistency over intensity. A small shift repeated often matters more than a dramatic overhaul that never sticks.
We’re On a Whole-Foods Mission, Too
Equip exists to make whole-food eating easy. We prioritize real food, minimal ingredients, and skip the fillers to support people who want fewer ultra-processed foods in their day.
Our products are not meant to solve fertility or metabolic health concerns. They simply offer a cleaner alternative that fits into routines built around intention.
Food Is More Than a Numbers Game
Food quality leaves fingerprints that nutrition facts cannot show. This study is a reminder that those layers matter in the bigger picture. Understanding them helps us navigate modern eating patterns with more awareness, not fear, and build a baseline rooted in deliberate choices rather than default habits.
Lauren Ciccarelli is a health and wellness writer with 10+ years of experience. Her 2,500+ articles make science simple and empower readers to thrive on their own terms.
