Food is one of the few things a couple trying to conceive can control, and most couples want to know they are doing it right. The good news is that research over the past fifteen years has given us a fairly clear answer: there is an eating pattern that is consistently associated with better fertility in women and better sperm quality in men, and it is neither expensive nor exotic. This article sets out what that research actually shows, how strong the evidence is, and what it looks like on a Sri Lankan plate. It builds on our broader guides to fertility and lifestyle and preconception care.

First, an honest note about the evidence

Almost everything we know about diet and fertility comes from observational studies — large groups of people whose eating habits were recorded and whose fertility was then tracked. These studies can show that people who eat a certain way conceive more easily; they cannot prove that the food is the reason, because people who eat well also tend to differ in weight, smoking, income and much else. Randomised trials, which would settle the question, are few. So the advice below is sound and low-risk, and it matches general healthy-eating guidance — but it is not a treatment, and no diet will overcome blocked tubes, severe sperm problems or the effect of age.

Is there a fertility diet?

No single diet. But one pattern keeps appearing in the research: an eating style built around vegetables, fruit, pulses, whole grains, fish, nuts and unsaturated oils, with little processed meat, few sugary drinks and few deep-fried or packaged foods. Researchers usually call this a Mediterranean or "prudent" pattern. In women it is associated with lower rates of ovulation-related infertility and better results from fertility treatment; in men it is associated with better sperm counts and motility. A 2023 review in Human Reproduction Update concluded that reducing trans fats, saturated fat, fast food and sugar-sweetened drinks was linked with better live-birth and pregnancy rates, while cautioning that there was not enough evidence to recommend any one named diet. The principle, not the label, is what matters.

This applies to men as much as women

A male factor contributes to around half of all fertility problems, and sperm are strikingly responsive to diet. A meta-analysis pooling studies of men's eating patterns found that those with the healthiest diets had sperm concentrations about 7 million per millilitre higher and progressive motility about 6 percentage points higher than those with the least healthy diets. In one small Italian study of young men, those eating the most ultra-processed food — packaged snacks, instant noodles, sugary drinks, processed meats — had markedly lower concentration and motility. Because sperm take about three months to form, dietary change needs that long to show in a semen analysis.

Eat more of

  • Vegetables and fruit — the single most consistent finding. Aim for colour and variety at every meal.
  • Pulses — dhal, chickpeas, cowpea, green gram, kadala. Plant protein in place of some red meat is associated with lower ovulatory infertility.
  • Whole grains — red or parboiled rice instead of polished white rice, kurakkan, whole-grain bread. Higher whole-grain intake has been linked with a thicker womb lining and better IVF outcomes.
  • Fish — including up to two portions of oily fish a week. Small oily fish such as hurulla, salaya and kumbalawa are rich in omega-3 and low in mercury. While trying and in pregnancy, do not eat shark, swordfish or marlin at all, and limit tuna to about two fresh steaks or four medium cans a week; treat seer (thora), another large predatory fish, the same way.
  • Nuts, seeds and unsaturated oils — peanuts, cashew, sesame (gingelly) oil, and a little olive oil if available.
  • Dairy — in moderation. Once blamed for infertility, it has not been consistently linked with harm; full-fat dairy may be slightly better for women, low-fat for men's sperm.

Eat less of

  • Trans fats — found in margarine, bakery products, biscuits and food fried in repeatedly reheated oil. These have the clearest negative association with ovulation; enjoying short eats occasionally is fine, but they should not be daily food.
  • Sugar-sweetened drinks — in Sri Lanka this is above all heavily sugared tea, as well as fizzy drinks and packet fruit juice. Linked with poorer fertility in both partners.
  • Ultra-processed and deep-fried food — fast food, instant noodles, packaged snacks, sausages and processed meat.
  • Large amounts of red meat — replacing some with fish, pulses or chicken is associated with better fertility.
  • Refined carbohydrates in excess — a plate that is three-quarters white rice with a spoon of curry drives up blood sugar and insulin, which matters particularly for women with PCOS. Reverse the proportions: half vegetables and pulses, a quarter rice, a quarter protein.

Coconut oil is high in saturated fat. It need not be abandoned — it is part of how we cook — but use it in moderation, never reuse frying oil, and let unsaturated oils and the fat in fish and nuts carry more of the load.

Weight: what it does and does not do

Being significantly overweight disrupts the hormones that drive ovulation, and in men lowers testosterone and sperm quality; being underweight stops ovulation altogether. For women with PCOS, losing even 5–7% of body weight improves ovulation rates and the response to ovulation-inducing medicines, as shown in randomised trials.

What weight loss does not reliably do is improve the result of fertility treatment. In a large randomised trial on the question, obese women with unexplained infertility who lost an average of 7% of their weight over four months before treatment had no higher chance of a healthy live birth than women who simply exercised without losing weight. So the honest message is this: aim for a healthy weight because it improves ovulation, makes pregnancy safer and is good for life — but do not let weight loss become a precondition that delays treatment for months, especially after 35, when time matters more.

Supplements: what is worth taking

  • Folic acid — the one supplement every woman trying to conceive should take, starting at least three months before. It prevents neural tube defects, and in fertility-clinic cohorts higher folate intake has been associated with better live-birth rates. Our preconception guide explains the 1 mg and 5 mg doses used in Sri Lanka.
  • Vitamin D — despite much enthusiasm, human studies show no clear effect on fertility unless you are deficient. Test if there is reason to suspect deficiency and treat it; do not take high doses as a "fertility" measure.
  • Vitamin B12 and iron — worth checking in vegetarian couples; deficiency affects both ovulation and sperm.
  • Antioxidant "fertility" blends (CoQ10, vitamin E, zinc, selenium, inositol and the like) — widely sold, expensive, and the evidence is weak. A Cochrane review of antioxidants for men found the evidence too poor to say whether they increase live births, and the evidence in women is no better. They are not harmful at sensible doses, but they are not a treatment, and no supplement should delay a proper fertility assessment.

Caffeine and alcohol — the numbers

Caffeine is less of a villain than it was once thought. Pooled studies show no association between moderate caffeine intake and the chance of conceiving, naturally or through IVF. Two or three cups of tea or coffee a day are fine; once pregnant, keep to under 200 mg a day (about two cups of coffee) because higher intake is linked with miscarriage.

Alcohol is different. In a meta-analysis of nineteen studies and nearly 100,000 women, any alcohol was associated with a 13% lower chance of conceiving per cycle, and the effect rose with the amount. In couples having IVF, more than about seven drinks a week in either partner reduced success. There is no proven safe level in early pregnancy. The simplest advice for both partners is to stop while trying.

A Sri Lankan plate for couples trying to conceive

  • Breakfast — kurakkan roti or red-rice string hoppers with dhal and a sambol; or oats with fruit. Tea with little or no sugar.
  • Lunch — a quarter plate of red rice, a fish or chicken curry, dhal or chickpeas, two vegetable curries and a mallung of green leaves (gotukola, mukunuwenna, kathurumurunga, sarana). A piece of fruit after.
  • Dinner — lighter: a vegetable soup, pittu or roti with pulses and vegetables, or a salad with boiled eggs or fish.
  • Snacks — fruit, roasted peanuts or kadala, curd, boiled green gram — instead of short eats and biscuits.
  • Drinks — water, king coconut, plain or lightly sweetened tea. Avoid fizzy drinks and packet juice.

About the foods we are often asked to avoid

Many couples come to us having been advised by family to avoid pineapple, papaya or "heaty" foods, or to take a particular fruit or supplement to help conception. This advice is given with love and usually comes from generations of experience, so it deserves a respectful answer rather than dismissal. The research simply has not found that any of these foods reduces the chance of conceiving or causes early loss; pineapple and papaya are nutritious fruits and perfectly safe to eat in normal amounts. Equally, no single food or supplement has been shown to bring on a pregnancy. If avoiding a food gives you peace of mind, there is no harm in it — but there is no need to feel anxious if you have eaten it. What the evidence points to is the overall pattern of eating over months, for both partners, rather than any one item.

The bottom line

  • There is no fertility diet, but a vegetable-, pulse-, whole-grain- and fish-based pattern is consistently associated with better fertility in women and better sperm in men.
  • Cut trans fats, sugary drinks, deep-fried and ultra-processed food; shrink the rice, grow the vegetables.
  • A healthy weight improves ovulation and pregnancy safety — but weight loss alone does not reliably improve treatment success, so don't let it delay care.
  • Folic acid is essential; most other supplements are not.
  • Moderate caffeine is fine; alcohol is best stopped by both partners.
  • Diet supports treatment; it does not replace assessment. If you have been trying for a year — six months if you are over 35 — see a doctor.

If you would like a fertility assessment alongside practical dietary advice for both of you, you can consult us at Sugabi Clinic Ragama or book a video consultation.

References

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