Foods and Fertility: What Is Proven and What Is Not

'Eat dates, drink fenugreek milk, avoid the cold.' When you are trying for a baby, dietary advice pours in, from your mother-in-law to social media. Some of it is harmless, some wastes time. What is the real link between foods and fertility?

The studies give a less spectacular answer than the promises, but a more useful one: no food makes you fertile, yet the whole of what you eat, your weight, smoking and alcohol all count, for women and men alike. Here is the sorting, evidence by evidence.

What the studies actually measure

First, a caution. Almost all the work on diet and fertility is observational: it compares what couples eat with how long they take to conceive. It shows associations, not causes. A 2025 review covering the Eastern Mediterranean region says so plainly: the predominance of such studies prevents any cause-and-effect conclusion.

The Harvard doctors who presented a major review on the subject sum up the spirit well: it is not a revolution. Eating healthily is already recommended to everybody, and that is mostly what the data confirm.

What seems to help

According to the review presented by Harvard Medical School, several elements are linked to better fertility in women trying to conceive naturally:

• Folic acid and vitamin B12. Folic acid is in any case recommended by the HAS (France's national health authority) from the moment you want to conceive, to protect the baby; your doctor sets the dose.
• Omega-3s, found in oily fish.
• A Mediterranean-style diet. The 2025 review cites a 2023 analysis in which strong adherence to this diet is linked to pregnancy and birth rates about a third higher.
• Fish: couples who ate more of it conceived faster. The ASRM does note, however, that very high seafood intake with high blood mercury has been linked to infertility: vary the species.

Good news: everyday Moroccan cooking is very close to it: olive oil, vegetables, pulses (lentils, chickpeas, broad beans), spices, fish. A vegetable tagine, a home-made harira or grilled sardines fit that model perfectly.

What seems to harm

The same review links lower fertility to:

• Trans fats, found in some industrial products, pastries and fried foods.
• A diet rich in red and processed meat (cold cuts), potatoes, sweets and sugary drinks.
• Sugary drinks in particular, linked to lower fertility in both women and men. Diet sodas and fruit juices did not show this effect in the studies cited. Remember also the sugar added to tea, which adds up fast when you drink several glasses a day.
• Fast food: women who ate it often and had little fruit took longer to conceive.

Coffee, alcohol, smoking: the real levers

Coffee and tea

No need to give them up. The ASRM finds no apparent effect with one to two cups of coffee a day; only heavy intakes, above five cups, are linked to lower fertility. The Mayo Clinic uses the same benchmark of one to two cups. Britain's NICE goes further: there is no consistent evidence of a link between tea, coffee or cola and fertility problems.

Alcohol

The ASRM links two or more drinks a day to a higher risk of infertility, and reminds us that no amount is safe during pregnancy. The simplest course, when trying to conceive, is therefore to go without.

Smoking

This is probably the heaviest factor. According to the ASRM, women who smoke are about 1.6 times more likely to be infertile and reach the menopause 1 to 4 years earlier. In men, NICE links it to poorer sperm quality. Stopping, together, does more than any menu change.

Weight: a factor that really counts

Being very underweight or markedly overweight lowers fertility, according to the ASRM. NICE specifies that a woman whose BMI is 30 or more generally takes longer to conceive, and that group programmes combining physical activity and dietary advice lead to more pregnancies than simple weight-loss advice. Conversely, in a very thin woman with irregular or absent periods, regaining weight improves the chances.

Beware of very restrictive diets and intensive exercise: the Mayo Clinic notes that very strenuous exercise can disrupt ovulation in a woman of normal weight. If you have PCOS, weight plays a particular role: see our article on PCOS and pregnancy.

Supplements and traditional herbs: be careful

'Fertility' supplements sold in pharmacies or online often contain vitamins, antioxidants, inositol or coenzyme Q10. The 2025 review finds some encouraging results on certain parameters (egg quality in PCOS, sperm motility), but inconsistent effects on what matters, pregnancy itself, and contradictory results for vitamin D. These products are only taken on medical advice, which also sets the dose.

Traditional herbs and mixtures, fenugreek (helba), nigella (sanouj), honey and pollen blends, herbalist preparations: none has proved effective. NICE reminds us that complementary medicines have not been properly evaluated for fertility. And a Moroccan study presented by Le Matin in 2021 notes that turning to traditional medicine mostly delays diagnosis and care. If pregnancy is slow to come, the right reflex is still a consultation, not a cure.

And the man?

Fertility is a two-person matter, and the future father's plate counts too. According to the review presented by Harvard, a healthy diet is linked to better sperm quality, and a diet rich in saturated or trans fats to poorer quality; alcohol and coffee seem to have little effect. NICE adds that obesity reduces male fertility and that smoking damages sperm.

Sperm take about two and a half months to form, the Quebec guide Mieux vivre reminds us: changes therefore pay off over several months. To understand the semen analysis and what can improve it, read our article on the sperm test.

Once you are pregnant, the rules change a little (cheeses, raw meat, fish): they are detailed in our guide to eating during pregnancy. And for the full set of tests to have before conceiving, see our guide to preparing for pregnancy.