Eating for Fertility: The Big Four and Beyond
By Keren Granit
Fertility isn’t something that starts the moment you decide to conceive. Long before ovulation tests, clinic appointments, or treatment plans, your body is constantly receiving signals that affect how your reproductive system functions. Hormones, metabolism, inflammation, and even environmental exposures all play a role in determining how easy or difficult it may be to get pregnant or sustain a healthy pregnancy.
What makes this field so promising is that many of these factors are modifiable. Scientific research from the past five years has identified a set of clear, evidence-based habits that can meaningfully support fertility. These are not quick fixes or miracle supplements. Instead, they’re rooted in nutrition, environment, and lifestyle patterns that shape the hormonal environment in which conception happens.
Among the many topics studied, four stand out as particularly well-supported: the Mediterranean diet; folic acid; reducing alcohol and smoking; and lowering exposure to common hormone-disrupting chemicals like per- and poly- fluoroalkyl substances (PFAS), Bisphenol A (BPA), and phthalates. These “Big Four” pillars form the strongest foundation for anyone trying to conceive.
The Mediterranean diet: where the evidence is strongest
If there’s one dietary pattern that stands out in fertility research, it’s the Mediterranean diet. Over the past decade, and especially in the last five years, multiple meta-analyses and cohort studies have consistently linked adherence to this way of eating with improved fertility outcomes. Women who follow a Mediterranean-style diet tend to have higher rates of conception, shorter time to pregnancy, and better results in assisted reproduction treatments like IVF and ICSI.
The Mediterranean diet isn’t a strict plan or a trend. It’s a pattern centered on vegetables, fruits, legumes, nuts, seeds, whole grains, and extra virgin olive oil as a primary fat source. Fish and poultry appear in moderate amounts, while red meat, processed foods, and added sugars are kept to a minimum. This pattern is naturally rich in antioxidants, fiber, and healthy fats, all of which contribute to metabolic and hormonal stability.
Why does it matter so much for fertility? One key reason is inflammation. Chronic low-grade inflammation is linked to poorer egg quality, ovulatory issues, and implantation problems. A Mediterranean pattern helps keep inflammatory markers low. It also supports insulin sensitivity and stable blood sugar, which is crucial for ovulation and reproductive hormone balance. For men, diets rich in omega-3s and antioxidants are associated with better sperm quality, motility, and morphology.
You don’t need to overhaul your kitchen overnight to benefit from this pattern. Shifting towards it can start with simple swaps: replacing white bread with whole grain; choosing olive oil instead of butter; opting for grilled fish instead of processed meats; and adding more colorful vegetables and legumes to your meals. Over time, these choices shape a more supportive hormonal and metabolic environment for conception.
Folic acid: a small nutrient with a big impact
While entire dietary patterns shape fertility in powerful ways, some specific nutrients have a uniquely well-established role. Folic acid is at the top of that list. For decades, it has been recommended to anyone who could become pregnant to help prevent neural tube defects. But growing evidence shows that its benefits start well before pregnancy begins.
Supplementing with 400 to 800 micrograms of folic acid daily at least one month before conception has been associated with better ovulatory function, improved egg quality, and lower risk of early miscarriage. It’s a simple, inexpensive intervention with high impact. Natural food sources, like leafy greens, legumes, and fortified grains do contribute folate, but supplementation remains standard because it ensures a consistent intake at levels proven to support early pregnancy.
Unlike many supplements that promise much more than they deliver, folic acid has decades of clinical data, guideline endorsements, and real-world impact behind it. If there is one supplement to prioritize pre-conception, this is it.
Alcohol and smoking: the basics that still matter
Some factors are so well established that they don’t need pages of explanation, but they still belong in any serious discussion of fertility. Alcohol and smoking—whether traditional cigarettes or vaping—have been repeatedly shown to impair fertility in both women and men.
Alcohol can disrupt ovulation and hormonal balance, increase time to pregnancy, and raise the risk of miscarriage. Smoking and vaping affect egg quality, reduce ovarian reserve, and damage sperm production and motility. Even moderate use can make a difference, particularly when conception chances each month are already limited.
For many people, cutting back or stopping these habits before trying to conceive is one of the most impactful things they can do, and it sets a strong foundation for a healthy pregnancy as well.
Hormone disruptors: the hidden fertility blockers
While smoking and alcohol are familiar territory, what many people overlook are the chemical exposures that quietly interfere with hormones. These are known as endocrine disruptors—chemicals that mimic or block natural hormones, essentially confusing the body’s signaling system. They’re not rare industrial substances; they’re present in many everyday products.
Three of the most discussed in fertility research are PFAS, BPA, and phthalates. PFAS, sometimes called “forever chemicals”, are found in nonstick coatings, stain-resistant fabrics, food packaging, and some drinking water. BPA and phthalates are commonly used in plastics and personal care products. Over the past few years, a growing number of studies have linked higher levels of these chemicals to reduced fertility, longer time to pregnancy, lower embryo quality, and impaired ovarian or sperm function.
The evidence isn’t just mechanistic; it’s increasingly supported by human data. Women and men with higher PFAS levels, for example, tend to have lower fertility rates, and couples undergoing IVF show lower success rates when exposure levels are higher.
The good news is that personal exposure can be reduced with practical steps. Using glass or stainless steel containers instead of heating food in plastic, choosing fragrance-free personal care products, limiting nonstick cookware when possible, and eating fewer highly packaged foods all lower contact with these chemicals. While we can’t control all environmental exposures, we can meaningfully reduce them in daily life.
Beyond the big four: what’s emerging
While the Big Four have the strongest evidence behind them, other factors are emerging as meaningful fertility influencers. One area gaining attention is ultra-processed foods (UPFs). Recent prospective cohort studies have found associations between high UPF intake and increased infertility risk. The explanation is likely twofold: these foods tend to displace nutrient-rich options, and they often come with higher exposure to packaging-related chemicals. Reducing their frequency—not eliminating them entirely—can support both overall health and reproductive goals.
Nutrient-wise, a few players are worth mentioning. Vitamin D has been linked to improved fertility outcomes, especially in people with deficiencies or conditions like PCOS, although the evidence isn’t yet strong enough to make it a universal recommendation. Omega-3 fatty acids support anti-inflammatory pathways and are associated with improved sperm quality and embryo development. Meanwhile, compounds like CoQ10 and inositol show promise in specific contexts, particularly in cases of PCOS or low ovarian reserve, but they remain adjunctive rather than foundational. These emerging factors can be seen as layers to build on, not substitutes for the basics.
Lifestyle habits that strengthen fertility
Nutrition and environmental exposures are only part of the story. Lifestyle factors also influence the hormonal and metabolic environment for conception. Sleep, for example, plays a surprisingly important role. Irregular or insufficient sleep can disrupt ovulation and lower fertility, while getting roughly seven to eight hours a night helps regulate reproductive hormones.
Chronic stress can also interfere with fertility through hormonal pathways. While stress alone does not cause infertility, managing it through approaches like mindfulness, CBT, or structured mind-body programs has been shown to improve emotional well-being and may increase the likelihood of conception, particularly in people undergoing fertility treatment.
Movement matters too. Regular, moderate physical activity supports insulin sensitivity, metabolic health, and egg quality. Intense or excessive exercise can have the opposite effect in some people, so balance is key.
Bringing the science home
Fertility isn’t something that switches on when you decide to conceive. It’s shaped by months of quiet, daily signals your body receives from food, environment, and lifestyle. The most powerful, well-studied actions don’t rely on expensive treatments or complicated trends. They’re accessible and evidence-based.
Start by building your plate around real food, adopting a Mediterranean-style diet pattern that supports hormonal balance and egg and sperm quality. Take folic acid daily, reduce alcohol and smoking, and cut everyday exposure to hormone disruptors like PFAS, BPA, and phthalates where you can.
If you have the energy to go further, look at cutting down ultra-processed foods, checking your vitamin D and omega-3 status, and taking care of your sleep, movement, and stress. These changes don’t guarantee pregnancy, but they stack the odds in your favor. They support reproductive health, general health, and pregnancy outcomes. Whether you’re trying naturally or preparing for treatment, these are actions that matter now.
About the Author
Keren Granit is a dietitian based in Bangkok, specializing in family and pediatric nutrition. She helps parents confidently guide their children’s eating habits, from picky eating to healthy growth. Passionate about evidence-based, practical advice, she shares resources and guidance at EatWithKeren.com.