When you’re trying to conceive — and especially if it’s taking longer than you expected  — assessing your nutrition and lifestyle choices is smart. However, the sheer volume of opinions on fertility nutrition is overwhelming and many of them are conflicting. 

You’ve probably heard all sorts of advice about what to eat (or avoid) when trying to conceive, but not all of it is backed by solid evidence. From avoiding meat to eating a Mediterranean diet, there’s a lot of information out there that’s not exactly accurate.

Plus, a lot of common fertility diet myths can cause unnecessary stress and some may actually reduce your nutrient intake and compromise hormone production and ovulatory function, which is not at all the best plan when you’re preparing for conception.

So, let’s bust some myths and get to the bottom of what really matters when it comes to nourishing your body and supporting your fertility. Ready? Let’s dive in!

5 Fertility Diet Myths

In this article, I’ll cover 5 fertility diet myths. These are some of the most common nutrition myths about fertility, namely that meat and dairy are harmful, the concept that a Mediterranean diet is best, that higher fiber intake is always beneficial to fertility, and that nutrition has nothing whatsoever to do with egg quality. 

Note: While I’m focusing on women in this article, much of the same advice applies to men and sperm quality as well. What supports your fertility is also good for your partner! (But if you need more specifics, see the sperm quality chapter of Real Food for Fertility). 

Myth #1: Meat is “bad” for fertility

The notion that a plant-based diet is best for our health, and that consuming meat is detrimental, has persisted for many decades. And it’s no different in the fertility space, where advice to lower meat consumption and follow a mostly plant-based diet is commonly recommended. Proponents of this approach are quick to point out supporting research, but have you ever taken a closer look at these studies? 

I have. I am continually shocked at the anti-meat bias in study design or methods and also the way in which some researchers discuss and present their findings. This can be seen in the title of the study, as well as the abstract, results, discussion, and conclusion.  Researchers can also manipulate the data analysis or presentation in a way to downplay any beneficial findings on meat or animal protein. And yes, some studies can have conflicts of interest based on the funding source or the dietary preferences of the authors.

Let me give you a few examples. In one study, dietary sources of protein were analyzed relative to their effect on ovulatory function. The title of the study suggested that plant proteins were superior, but at closer analysis of their findings, the only plant protein category that was actually supportive of ovulatory function was legumes. The “meat alternatives” category — aka fake meat — was actually associated with worse ovulatory function (it scored worse than any of the animal protein categories, by the way). And yet, their study title and abstract did not differentiate between the type of plant protein, nor did it acknowledge that many animal protein sources were also beneficial (or net neutral) in their effect on ovulatory function. Even processed meat scored better for ovulatory function compared to all plant protein categories, with the exception of legumes. 

In another study, researchers looked at associations between various protein sources and treatment outcomes from assisted reproductive technology, such as IVF. The study concluded that fish consumption was related to a higher probability of live birth following fertility treatment. Interestingly, red meat was also shown to improve the rates of live birth (to the same degree as fish intake), but this finding was not highlighted in the study abstract or conclusion; it was only briefly mentioned in the results section in the full text of the paper. Since most clinicians don’t have the time to read full research papers, they’re often just relying on the highlights in the abstract of a paper (or even the title of the paper). And sadly, this rarely tells the full story.

In other studies, I’ll see positive findings about meat left out of the discussion. In a large epidemiological study that specifically looked at ovulatory function in women relative to their diet, women who ate the most animal protein (a difference of about 3.5 oz of animal protein daily) actually had the lowest rates of ovulatory infertility. However, despite this relevant and noteworthy finding, it was only briefly mentioned in the results section of the study. What is especially fascinating about this is that the women who consumed the most meat were more likely to have other dietary and lifestyle factors that are typically detrimental to fertility, including higher alcohol consumption, cigarette use, and being inactive. The researchers never stopped to ask whether they had miscategorized meat as being “unhealthy” or whether the higher meat consumption may have had a protective effect.

Another issue is when some study designs try to rank a “healthy” or “unhealthy” dietary pattern, by awarding points towards factors like vegetable consumption and low sugar intake, and deducting points towards factors like smoking and alcohol consumption. But you know what else is typically included in the list of “unhealthy” habits? Meat intake. For studies that use this design, any beneficial (or neutral) effects of meat consumption on fertility are diluted because the findings are presented as an aggregate of all of these factors. While I generally like seeing researchers consider dietary patterns (versus only considering a single dietary factor), this type of study design doesn’t give us enough information to draw any strong conclusions on individual dietary factors. I actually found it a bit ironic that in one study (that is widely cited in the fertility space), the lowest rates of ovulatory infertility were found in women who consumed the most animal protein, but of course, they minimize this finding in their paper.

There are countless other examples of studies in which the titles or summaries misrepresent the actual data, but I’ll stop here. For more detailed examples, read the section in Chapter 5 in Real Food for Fertility entitled “But I was told that meat is bad for fertility. Is that true?”.

We also must zoom out when considering nutrition research and consider the bigger picture. What are the micronutrients — vitamins, minerals, etc. — that support eqq quality, ovulatory function, and pregnancy outcomes? And where do we find these in whole foods? These simple questions are ones that are often glossed over in the silos of academia. We’ll have paper after paper come out on the benefits of amino acids, like L-carnitine, for various markers of fertility, yet no one stops to ask where we get that nutrient from food. I’ll tell you: red meat.

Addressing this myth alone could fill another 10,000 words — words that are already written in Real Food for Fertility, so to wrap up, I’ll simply quote a small section from the book. But I implore you to thoroughly read chapters 2, 3, and 5 for a more thorough rebuttal to the myth that meat is harmful to fertility. 

“The next time someone tells you that meat is harmful to fertility, critically examine the source of this claim. At the time of writing, we have yet to come across reliable data showing that animal protein is outright harmful to fertility. If anything, our thorough review of the evidence has shown that the high-quality protein, specific amino acids, fatty acids, and micronutrients found in animal protein are absolutely vital to optimal fertility. Keep in mind that you have to read all studies in their entirety, including the methods and data. A shockingly high percentage of papers either misinterpret or fail to acknowledge key findings in their abstract, discussion, and conclusion.” – Real Food for Fertility

Myth #2: The Mediterranean diet is “proven” to be the best diet for fertility

Many fertility professionals suggest a Mediterranean diet to optimize fertility. And while this is often an improvement over a standard American diet, it’s not always the best approach. Let me explain.

We first have to acknowledge that the typical American definition of a Mediterranean diet used by researchers is not at all an accurate reflection of what is traditionally consumed throughout that region. I’ve detailed these issues in another article. In short, our modern interpretation of a Mediterranean diet is exceedingly low in animal protein, animal fat, and often pushes an unnecessarily high intake of grain-based carbohydrates.

That said, there are some positive aspects of a Mediterranean diet (even if the interpretation of such a diet is not regionally or historically accurate). Namely, it prioritizes whole foods over processed foods. This is a very positive shift for most Americans, who are (on average) getting 58% of their calories from ultra-processed foods. This is a major reason why research studies find improvements in fertility (such as with PCOS and IVF success rates) when switching participants from a standard American diet to a Mediterranean diet.

However, not all studies on fertility have found that the Mediterranean diet benefits fertility (at least, the low-fat version implemented by most research study protocols). For the sake of clarity, I’ll refer to this as a “conventional Mediterranean diet.”

Women who follow this type of diet — one that’s low in meat but high in grains, legumes, vegetables, fish, and fruit — have a significantly higher incidence of having a short luteal phase (less than 10 days).  You might think that this is because these women are eating fewer calories or maybe their older or some other factor explains this association. But this observation held true for these women despite similar energy intake, age, and body fat percentage of women with normal cycles.

Why would a short luteal phase matter to fertility? The luteal phase is the time between ovulation and the start of the next menstrual period. In women who are trying to conceive, the luteal phase is the time in which implantation takes place. If the luteal phase is too short — an indication of low progesterone — implantation often cannot occur. This means a short luteal phase can impact your ability to become pregnant or sustain a pregnancy. 

As I point out in Real Food for Fertility, “It’s not that anything included in the conventional Mediterranean diet is problematic; it’s more about what is missing.”

And what is missing from a conventional Mediterranean diet? Sufficient animal protein and animal fat. 

For many women, a switch to a conventional Mediterranean diet means not consuming enough of these key nutrient-dense foods. So yes, while they may have increased their intake of fresh fruits and vegetables and reduced their intake of processed foods, they may now be falling short on adequate protein, fat, or even overall calories. 

The misinterpretation of what a traditional Mediterranean diet does (or does not) include can be detrimental to fertility in the long term. You may see some initial improvements from the exclusion of processed foods; however, minimizing key nutrient-dense foods eventually compromises hormone production and ovulatory function. 

And just to level set here, there are studies that support the inclusion of red meat specifically as part of a Mediterranean diet, that have not found negative effects on health (even when red meat is included at levels typical in American diets). 

As I state in Real Food for Fertility: 

“Ultimately, you can take the good parts of a conventional Mediterranean diet — fresh produce, olive oil, fish, and other unprocessed foods — while still embracing other dietary traditions of the region.” 

If you’re having trouble wrapping your brain around the concept that “forbidden” foods, like red meat and full-fat dairy, could be helpful for your fertility, I encourage you to keep an open mind and read Chapters 2, 3, and 5 of Real Food for Fertility.

Myth #3: Egg quality is fixed; dietary changes “can’t” improve egg quality

One common myth that persists in some fertility circles is the belief that nutrition has no impact on egg quality. This misconception suggests that the quality of a woman’s eggs is predetermined and unchangeable, yet this is not the case. Emerging research in this area shows that diet, lifestyle, and metabolic health can play a significant role in improving egg quality. This includes factors such as nutrient intake, blood sugar levels, thyroid function, and levels of inflammation. 

When we think about egg quality, we must think first about metabolic health. That’s because a human egg cell has more mitochondria than any other type of cell. These tiny organelles are the energy-producing “batteries” of our cells. Mitochondrial health underpins our metabolic health.

To quote a fascinating statistic from Real Food for Fertility, “Every cell in the body contains anywhere from a few hundred to several thousand mitochondria, and they collectively produce more than 90% of the body’s energy. With anywhere from 100,000 to 600,000 mitochondria, each egg cell contains more than any other cell in the body.”

Issues with mitochondrial function underscore a variety of chronic health and metabolic issues as well as fertility challenges. Mitochondria regulate the development of egg cells in preparation for ovulation (called folliculogenesis), fertilization, implantation, the development and growth of the human embryo (embryogenesis), and the development of the placenta.

Numerous nutrients play a role in egg quality, much of which is explained by their impact on mitochondrial function. As we discuss in Real Food for Fertility,

“Micronutrients required for healthy mitochondrial function include vitamins E, C, D, B1, B2, B3, B6, B12, folate, biotin, choline, inositol, methionine, taurine, magnesium, iron, zinc, copper, iodine, selenium, alpha lipoic acid, and CoQ10.”

Many research studies in the realm of assisted reproductive technology specifically focus on supplementing with some of these nutrients (or boosting dietary intake) to help improve the chances of success with procedures like IVF. There’s also studies showing that dietary intake of certain nutrients or foods — full-fat dairy and organ meats being two examples — may help support egg quality (as evidenced by higher AMH levels) in women who consume these foods.

This just scratches the surface of the research available on supporting and improving egg quality. I encourage you to read the very detailed chapter on egg quality in Real Food for Fertility for more information. But suffice it to say, if someone tells you that diet and nutrition has no impact on egg quality, I can assure you that they are misinformed.

Myth #4: More fiber is always “better” for fertility and hormone balance

Fiber is generally considered beneficial for fertility due to its role in hormone regulation, blood sugar control, and gut health. However, it’s important to acknowledge that there can be too much of a good thing.

On the positive side, fiber slows the digestion of carbohydrates, helping to maintain stable blood sugar levels. Blood sugar stability is important for fertility because it supports overall hormonal balance, minimizes inflammation, supports optimal egg and sperm quality, and reduces the risk of conditions like polycystic ovarian syndrome (PCOS).

Fiber also supports digestive health by increasing motility (which helps prevent constipation) and fueling a healthy microbiome (fiber acts as a prebiotic for the good bacteria in our gut). 

And finally, fiber is beneficial for detoxification and hormonal balance as it binds excess estrogen metabolites and toxins, which are then excreted in stool so they are not reabsorbed.

Overall, women who consume a sufficient amount of fiber tend to conceive faster than women who eat a low-fiber diet. This can be, in part, due to the fiber itself or because fiber intake is usually a proxy of a better quality diet (generally, the less processed food you consume, the higher your fiber intake). Altogether, most research supports the benefits of consuming enough fiber for optimal fertility.

But does this mean you should eat as much fiber as you possibly can? Not so fast!

While moderate fiber intake helps balance hormones, excessive intake may lead to an over-excretion of estrogen. This could potentially disrupt the delicate hormonal balance necessary for ovulation and a regular menstrual cycle.

In research that I highlight in Real Food for Fertility, women with a high intake of fiber have an 11-times-higher risk of anovulatory cycles compared to women with low fiber intake (anovulatory means they do not ovulate in that menstrual cycle). When the researchers looked specifically at the type of fiber, women who consumed the most fiber from fruit and grains had significantly lower estrogen and progesterone levels (notably, vegetable fiber was not associated).

From my clinical experience, some women who prioritize fiber intake too much can end up under consuming calories as well. Fiber helps them feel full, but at the expense of not consuming enough energy from food! If this is the case, you have both under-production of hormones (from limited nutritional resources) and over-excretion of hormones (from excess fiber).

Excessive fiber intake, particularly from supplements or extremely high-fiber diets, can also interfere with the absorption of important nutrients like iron, zinc, calcium, and fat-soluble vitamins. These nutrients are essential for reproductive health and fetal development, so impaired absorption could be detrimental to fertility from the angle of impaired nutrient absorption. 

Hormones are always in a delicate balance and fiber serves as a good reminder that more is not always better. While excess estrogen is certainly problematic, too little estrogen can be just as damaging. Estrogen plays a number of roles in female fertility, most notably in preparing the ovarian follicles, triggering ovulation, and thickening the endometrial lining.

While including fiber-rich foods — like vegetables, raspberries, avocado, legumes, chia seeds, shredded coconut, etc. — is a good call for supporting fertility, there’s no need to go crazy here. The moderate quantity of fiber you consume from whole foods in a balanced, omnivorous diet is plenty.

If you want to see more specifics on what to include in a daily eating pattern for optimal fertility, you get a week’s worth of meal plans in Real Food for Fertility. 

Myth #5: Dairy is “inflammatory” and must be avoided to optimize fertility

The wellness space has no shortage of opinions on dairy, that’s for sure. While I won’t argue that dairy is required from a fertility perspective, it certainly has its benefits.

In fact, plenty of research has shown that dairy has direct benefits to female hormones. 

Some specific studies which highlight this effect are cited in Real Food for Fertility: 

“Women with a higher intake of dairy, specifically full-fat dairy, have been found to have higher luteinizing hormone levels and lower testosterone levels across their cycles. In addition, dairy consumption is protective against the typical age-related decline in anti-Müllerian hormone (AMH) levels — a marker of ovarian reserve. These beneficial findings on hormone levels are consistent with the research showing improved fertility and IVF outcomes (highest chance of a live birth) in women who consume the most high-fat dairy products.”

The benefits of dairy and fertility can be attributed to the variety of nutrients it provides. Calcium may be the first thing that comes to mind for many, but it also provides key fat-soluble vitamins such as vitamin A, D, E, and K2. 

Vitamin K2 (found in highest amounts in fermented dairy products such as yogurt, cheese, kefir) may help increase insulin sensitivity, which helps keep blood sugar balanced. It may also influence egg quality by reducing oxidative stress (and therefore reducing inflammation).  

B-vitamins are also found in dairy products, most notably riboflavin, which supports folate metabolism and keeps homocysteine (an amino acid that is associated with inflammation) in check. This matters because high homocysteine has been associated with higher miscarriage rate and reduced fertility. Dairy products also provide iodine, which may be lacking in those who omit or limit seafood from their diet. 

Beyond all the nutrients mentioned, dairy also provides a source of probiotics (if unprocessed and/or fermented) and even a decent source of protein – both with fertility benefits in their own right.

All this to say, dairy is a nutrient-dense food and can fill common nutritional gaps in the diet. For instance, dairy products may be the only source of vitamin B12 and retinol (along with eggs) for vegetarians. For those who omit seafood from their diet, it may be the only major source of iodine in their diet (eggs also provide this if they are included).

Now let’s be clear — not all dairy is created equal. The low-fat, highly processed versions may not have all of the same benefits as full-fat, minimally processed dairy products. Whenever possible, aim to source dairy products that are full-fat, organic, and grass-fed or pasture-raised to reap as many benefits as possible. If you are sensitive to lactose or have digestive issues, give raw, fermented, or A2 dairy products a try as they are more easily digestible for many individuals.

We cover a LOT more detail on dairy products, including the benefits and controversies surrounding its consumption, our thoughts on raw milk, and much more in chapter 3 of Real Food for Fertility.

Be careful not to fall for fertility diet myths

At the end of the day, the world of nutrition and fertility is rife with conflicting opinions. As social media increasingly becomes a go-to source for information, you have to really be careful what information you believe.

And I have a lot of compassion for those of you in the midst of fertility challenges trying to make sense of it out there. It’s overwhelming — even for me!

What I’ve learned from working in this field and diligently reading thousands of research articles in the writing of Real Food for Fertility — yes, over 2,300 studies are cited in the book! — is that fertility research is some of the most challenging to get right. There’s commonly issues with the methods, bias in the interpretation or presentation of the results, and blatant conflicts of interest. You really have to do your due diligence when vetting, reading, and interpreting studies.

My goal with my writing is to try and simplify this for you. I know many of you may not enjoy the tedious process of finding and analyzing research, but I do!

I hope that after reading this article, you can better see the truth behind popular misconceptions about diet and fertility. There are so many more, so if this is an area you want to dive into, grab a copy of Real Food for Fertility. It’s now available in paperback, ebook, and audiobook formats.

If you’d like a preview of the book, you can download the first chapter for free here.

Until next time,

Lily

 

PS — Let me know in the comments which of the myths you found most interesting. If you’ve come across any other fertility diet myths that you want my opinion on, drop them in the comments. I’ll keep an eye on these and consider a follow up post here on my blog or on Instagram to address them.

PPS — Are you a registered dietitian? If so, you can earn 48.5 CEU credits from Real Food for Fertility. Go here to learn more and redeem your continuing education credits. 

 

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