For a long time, fertility advice has been directed almost entirely at women (not here at Red Tent of course but in life – out there – it’s more been on women’s shoulders).
But a very recent 2026 study published in Human Reproduction shifts that perspective in a meaningful – and important – way: What both partners eat in the months leading up to conception directly influences fertility and early embryo development.
What the Study Actually Found
This large prospective cohort study followed:
- 831 women
- 651 male partners
and assessed their intake of ultra-processed foods (UPFs) — things like packaged snacks, processed meats, ready meals, and foods high in additives and low in nutrients.
Here’s what they found:
- Higher maternal intake of ultra-processed food was associated with
→ smaller embryonic size (crown-rump length) at 7 weeks
→ smaller yolk sac volume at 7 weeks - Higher paternal intake of ultra-processed food was associated with
→ reduced fertility (lower chance of conceiving each cycle)
→ increased risk of subfertility
This is significant because it’s the first study to look at both partners together – and to measure effects not just on conception, but on the embryo itself in early pregnancy.
This Starts Earlier Than You Think
One of the most striking parts of this study is when the effects were seen.
At just 7 weeks of pregnancy, measurable differences in embryo size and yolk sac development were already present.
The yolk sac is critical in early pregnancy – it provides nutrients to the embryo before the placenta fully takes over.
So what this tells us is:
The environment that shapes a baby doesn’t begin at conception.
It begins months before.
Why Ultra-Processed Food Has This Effect
Ultra-processed foods tend to be:
- low in fibre
- low in micronutrients
- high in sugars, unhealthy fats, and additives
- disruptive to the gut microbiome
This creates a cascade of effects:
- increased inflammation
- poorer metabolic health
- impaired hormone signalling
- reduced egg and sperm quality
So by the time conception occurs, the “building blocks” are already compromised.
From a Chinese Medicine Perspective
This study beautifully reflects something that has always been foundational in Traditional Chinese Medicine:
Fertility is never just about the woman.
Both partners contribute essential substances:
- The woman provides Blood and the uterine environment
- The man provides Jing (essence) through sperm
If either is compromised, the outcome is affected.
The Role of the Spleen and Stomach
In Chinese medicine, everything begins with digestion.
The Spleen and Stomach are responsible for transforming food into:
- Qi (energy)
- Blood (nourishment)
- Jing (reproductive essence)
When the diet is made up of highly processed, nutrient-poor foods:
- the Spleen becomes weakened
- Dampness and Heat accumulate
- the production of Blood is compromised
This leads to an internal environment that is:
- inflamed
- poorly nourished
- less able to support conception and early development
Modern language might call this metabolic dysfunction or microbiome disruption.
Chinese medicine has always described it as a breakdown in the Spleen and Stomach system.
Why the Male Matters Just As Much
One of the most important findings here is the role of the male partner.
Higher intake of ultra-processed food in men was associated with:
- lower fecundability (reduced chance of conceiving each month)
- higher likelihood of subfertility
This reinforces what we already know:
Male factors contribute to around 40–50% of fertility challenges.
From a Chinese medicine perspective:
- Sperm is an expression of Kidney Jing
- Poor diet → weakens Jing → reduces the quality of what is contributed at conception
So even if the woman is doing everything “right,” the outcome is still shared.
What This Means Practically
If you are preparing for pregnancy, this research suggests:
Both partners should:
- reduce ultra-processed foods
- prioritise whole, nutrient-dense foods
- support digestion and gut health
- minimise inflammatory inputs
Because what you are doing in the 3-4 months before conception is directly shaping:
- egg quality
- sperm quality
- and the earliest stages of embryonic development
Because it takes 3-4 months to create ONE sperm and to mature ONE egg.
Chinese Medicine Has Always Focused on Preconception
What’s so interesting is that none of this is new in Chinese medicine.
For centuries, preconception care has involved:
- treating both partners
- strengthening digestion
- building Blood
- preserving Jing
- preparing the body for at least 3 months before trying to conceive
Not because of modern research.
But because clinically, it led to better outcomes.
Final Thought
This study gives us modern evidence for something deeply intuitive:
You don’t start building a baby at conception.
You start months before – and you do it together.
Your food, your digestion, your daily habits – they all become part of the blueprint.
And when both partners are supported, you’re not just improving your chances of conception…
You’re creating a stronger, more supported beginning for the life that follows.
Interested to find out how you and your parterner can improve your chances of a healthy conception, get in touch today.
Reference:
Lin, C.H.X. et al. (2026). Periconceptional ultra-processed food consumption in women and men, fertility, and early embryonic development. Human Reproduction. https://doi.org/10.1093/humrep/deag023