When you’re about to start IVF, it’s only natural to wonder if there’s anything you can do to improve your chances of success. Nutrition is one of the areas that often comes up, and rightly so—what you eat fuels your body, affects your hormones, and plays a role in overall reproductive health. But how much does it really matter when it comes to IVF outcomes? Well, some fascinating research suggests it might matter quite a bit.
It’s not just about how much you eat—it’s about what you eat. A fertility clinic in California conducted a study that compared the eating habits of women undergoing IVF. The study focused on a group of women who, on paper, should have been perfect IVF candidates. These women were young, had normal BMIs, and good ovarian reserves. But despite this, they didn’t respond well to fertility drugs, produced fewer eggs, had lower-quality embryos, and experienced more miscarriages.
The clinic asked the women to keep food diaries, and the results were eye-opening. Although they were eating the right number of calories (around 2,000 kcal per day, ideal for active young women), most of these calories—over 75%—came from carbohydrates. Think cereal and toast for breakfast, sandwiches for lunch, pasta for dinner, with crisps and biscuits in between.
In contrast, women who had more successful outcomes ate very differently. Their diets included more protein, fresh fruit, and plenty of leafy green vegetables. These women’s live birth rates were almost double those of the “high-carb” group.
Why does protein make such a difference?
Protein plays a vital role in supporting egg quality and embryo development, which is likely why it’s so beneficial for women undergoing IVF. A protein-rich diet has a more favourable impact on blood sugar levels throughout the day, which is particularly important for women with conditions like polycystic ovary syndrome (PCOS).
For women with PCOS, who often struggle with insulin resistance, cutting down on carbohydrates and focusing on lean proteins and healthy fats can not only help with weight loss but also improve their overall fertility. This approach isn’t just for women, either—men can benefit from dietary changes too.
Nutrition and sperm quality
If you’re in a relationship where male fertility is part of the picture, it’s worth knowing that what your partner eats can impact sperm quality. Sperm takes on average 70 days to develop, so changes in diet will need at least two-three months to show results. Overweight or obese men may see an improvement in sperm health by losing weight and adopting a healthier eating plan.
This shared focus on diet and nutrition can also be a great way to support each other during what can be an emotionally challenging time.
One diet that consistently comes up in fertility research is the Mediterranean diet, and with good reason. A major study published in Human Reproduction, a leading fertility journal, looked at the diets of women undergoing IVF. The findings were striking women who followed a Mediterranean-style diet were almost twice as likely to achieve a live birth compared to those who ate more ultra-processed foods and fewer fresh, whole ingredients.
It also limits red meat, ultra-processed foods, and simple carbohydrates, which can have a negative impact on overall health and fertility.
Interestingly, the research found that the benefits of a Mediterranean diet were most significant for women aged 35 and under. For women over 35, other factors, like egg quality and ovarian reserve, often play a larger role.
Vitamin D, often called the “sunshine vitamin,” plays a crucial role in fertility. Research shows that women deficient in vitamin D may experience lower IVF success rates.
A pooled analysis found that infertile women treated with vitamin D supplements had significantly higher clinical pregnancy rates compared to those who didn’t take supplements.
You can get vitamin D naturally from sunlight, oily fish, eggs, and fortified foods, but supplementation is often necessary—especially in the UK, where sunlight is limited. Vitamin D sprays are an excellent option, as they’re easy to use and quickly absorbed.
Folic acid is widely recognised for its role in preventing neural tube defects, but it also has a crucial impact on fertility treatment. Studies suggest that higher intake of folic acid, particularly from supplements, is associated with better egg quality, improved embryo development, and increased chances of pregnancy.
One study found that women with higher folate intake had greater live birth rates after assisted reproduction. Additionally, folic acid has been shown to reduce the time to conception and lower the risk of ovulatory infertility.
You can find folic acid naturally in leafy greens, fruits, vegetables, and fortified foods, but for those
undergoing IVF, a daily supplement is highly recommended. Folic acid supplements are inexpensive and widely available online, in chemists, or in health food shops.
Alcohol is a well-known factor that can harm fertility, particularly for men. It damages the sperm-producing cells in the testicles and disrupts hormone levels, both of which can reduce sperm quality.
A study of more than 1,200 Danish men aged 18-28 found that those who drank as little as five units of alcohol a week—around three beers or glasses of wine—had lower sperm counts and poorer sperm quality compared to non-drinkers.
For women, alcohol may also reduce the likelihood of conception and increase the risk of miscarriage. Cutting out or reducing alcohol while preparing for IVF is a simple but effective way to improve both egg and sperm quality.
High sugar intake can negatively impact IVF outcomes, as it affects blood sugar levels and overall egg quality. A Japanese study found a direct link between sugar consumption and fertility outcomes. Women who consumed more sugar in the months leading up to their IVF cycle had poorer-quality eggs and lower pregnancy rates.
By reducing sugar intake—avoiding sugary snacks, fizzy drinks, and ultra-processed foods—you can help stabilise your blood sugar levels and create a more supportive environment for your fertility journey.
While a morning coffee might feel like a staple, it’s important to keep caffeine intake in check during fertility treatment. Research has linked excessive caffeine consumption to complications such as low birth weight, miscarriage, and stillbirth during pregnancy.
If you’re preparing for IVF, reducing your caffeine intake to one or two cups of coffee a day—or switching to decaf—is a good way to support your fertility and overall health.
One key takeaway from this research is that dietary changes need time to take effect. The eggs you’ll use in an IVF cycle actually begin developing about three months before treatment starts. That means the choices you make today could influence your fertility in a few months' time.
If you’re thinking about tweaking your diet, aim to start at least 2-3 months before your IVF cycle begins. The same goes for your partner if sperm quality is a factor—improvements there also take time.
Improving your diet doesn’t have to mean overhauling everything overnight. Start with small, sustainable changes, like adding more fresh fruit and veg to your meals or swapping out ultra-processed snacks for nuts or seeds. Gradually increase your protein intake by incorporating lean meats, fish, or plant-based options like lentils and chickpeas.
And don’t be too hard on yourself—it’s okay to treat yourself occasionally. This journey is challenging enough without feeling guilty for enjoying a biscuit now and then.
References