Nutrition in Pregnancy: Fact or Fiction?

The most persistent myths, examined with the clarity you actually need

There is a particular kind of exhaustion that comes not from physical tiredness but from information overload. If you are pregnant, you know exactly what this feels like.

Your mother-in-law has a theory about peanuts. A colleague mentioned something about iron. Three different apps are telling you three different things about how much to eat. And underneath all of it is this quiet sense that every food choice carries consequences you cannot fully calculate.

It is a lot. And much of it is unnecessary.

Because here is the truth: a significant portion of what circulates as pregnancy nutrition advice is not grounded in current evidence. Some of it is outdated. Some of it was never accurate to begin with. And some of it, left unaddressed, can lead to choices that actually compromise rather than protect your health and your baby's.

This article examines four of the most persistent myths in detail. Not to add to the noise, but to help you cut through it with a clearer understanding of what the science shows.

Myth 1: Avoid Peanuts During Pregnancy to Prevent Allergies

Few pieces of nutrition advice in pregnancy have spread as widely, or persisted as stubbornly, as the recommendation to avoid peanuts. The reasoning is intuitive: peanuts are a common allergen, so removing them from the maternal diet during pregnancy must reduce the child's risk of developing a sensitivity later.

Current evidence does not support this conclusion.

Research consistently demonstrates that maternal avoidance of allergenic foods during pregnancy has no measurable protective effect on childhood allergy development. Major allergy research bodies, including the World Allergy Organization, have moved decisively away from avoidance-based recommendations. The more nuanced picture that research now presents is one in which early exposure, including prenatal exposure through the maternal diet, may in fact support the development of immune tolerance rather than trigger sensitisation.

The clinical guidance is clear: unless you personally have a diagnosed peanut allergy, there is no evidence-based rationale for avoiding peanuts during pregnancy. Restricting your diet in ways that are not clinically indicated adds unnecessary complexity to an already demanding nutritional period, often without any benefit and sometimes at a genuine nutritional cost.

The takeaway: eat peanuts freely unless you personally are allergic to them. Do not restrict your diet based on fear of passing on an allergy you do not have.

Myth 2: What Season You Conceive In Does Not Matter

This one is more nuanced and, honestly, more fascinating than most people realise.

Across many cultures and centuries, there has been a belief that the time of year a baby is conceived influences that child's long-term health. In Ghana and across sub-Saharan Africa, where seasonal cycles of plenty and scarcity are pronounced, this belief has deep roots. And it turns out the science is beginning to validate what generations of observation had already noticed.

Research into populations where seasonal food availability varies significantly has found that conception during periods of nutritional deficit can have measurable effects on a child's health outcomes that persist well into childhood and beyond. The nutritional environment in those earliest weeks of development, before many women even know they are pregnant, leaves a biological imprint.

But this is not only relevant to regions of food scarcity. Even in northern Europe and Switzerland, there are significant seasonal variations in vitamin D status. Clinical trials have demonstrated that low maternal vitamin D around conception and in early pregnancy, which is extremely common in the winter months at northern latitudes, is associated with poorer bone development in children. Crucially, correcting that deficiency through supplementation improves outcomes not just in infancy but measurably throughout later childhood.

The practical message is this: your nutritional status in the months before pregnancy matters just as much as what you eat once you know you are expecting. Pre-conception nutrition is not an afterthought. It is the foundation. And vitamin D is a particularly important piece of that foundation if you are living in Switzerland and trying to conceive in autumn or winter.

Myth 3: You Are Eating for Two

You have almost certainly heard this. You may have even said it yourself, with a smile, reaching for a second portion.

And the sentiment behind it is lovely. You are growing a human being. That deserves acknowledgment, celebration, and yes, nourishment.

But the literal interpretation, that your caloric needs have doubled, is not accurate. And it matters, not because pregnancy is a time for restriction, but because understanding what your body actually needs helps you eat in a way that genuinely supports you rather than just adding volume.

The additional energy requirement in pregnancy is modest. In the first trimester, it is close to zero. It increases gradually through the second and third trimesters, reaching an additional intake of roughly 10% above your normal baseline at most. Not double. Not even close to double.

What changes far more significantly than the quantity is the quality of what your body needs. The demand for specific nutrients, folate, iron, iodine, DHA, vitamin D, choline, calcium, increases substantially. This means that the most important thing you can do is not eat more of everything. It is eat more of the right things, consistently, with attention to nutrient density rather than portion size.

Eating for two is a myth. Nourishing one body that is doing extraordinary work, intelligently and enjoyably, is the reality.

Myth 4: Iron Supplements Will Affect Your Baby's Skin Colour

This myth exists in several cultural contexts, most notably in parts of South Asia, and it needs to be addressed directly because the consequences of following it are serious.

The belief is that iron supplementation during pregnancy affects the skin colour of the baby. It does not. The skin colour of a child is determined entirely by genetics, by the combination of genes inherited from both parents. Nothing in the mother's diet, whether iron, dark chocolate, black tea, or any other food or supplement, has any effect on it whatsoever. This has been clearly and repeatedly established by science.

What iron deficiency during pregnancy absolutely does affect is the health of both mother and child.

Iron is essential for the production of haemoglobin, the molecule in red blood cells that carries oxygen through the body. When a pregnant woman becomes anaemic through insufficient iron intake, there is less oxygen available to be transported via the placenta to the developing fetus. And reduced oxygen to a growing baby is not a minor concern. It is a documented risk factor for complications affecting fetal growth, development, and the mother's own health and recovery.

Anaemia in pregnancy is genuinely dangerous. If your blood results indicate low iron, or if your healthcare provider recommends supplementation, this is one recommendation that should not be set aside based on cultural belief or dietary myth. Your baby's skin colour will be determined by their genes. Their development in the womb will be determined, in part, by how well nourished you are.

What These Myths Have in Common

None of these beliefs are malicious. They come from culture, from tradition, from generations of women trying to protect their babies with the information available to them at the time. That impulse is beautiful. It just needs to be guided by current evidence rather than outdated assumption.

What I notice, working with pregnant women, is that the myths that cause the most harm are the ones that lead to unnecessary restriction. Avoiding foods that are perfectly safe. Skipping supplements that are genuinely necessary. Eating less out of fear rather than more of what actually matters.

The goal of evidence-based nutrition in pregnancy is not to add more rules to your life. It is to remove the ones that were never grounded in science in the first place, and replace them with a clear, practical, enjoyable approach to eating that supports you and your baby without the noise.

You are already doing something remarkable. You deserve information that makes that feel easier, not harder.

Sources:

Prescott SL et al., World Allergy Organization, 2013. Boucher BJ, Vitamin D status in pregnancy and early life, Proceedings of the Nutrition Society, 2012. Prentice AM et al., Seasonality and early nutrition in Africa, Public Health Nutrition, 2009. World Health Organization, Nutritional anaemia in pregnancy, 2016.

Margherita Laviani | PN Level 1 Certified Nutrition Coach | Fertility, Pregnancy Nutrition Lifestyle (LMU Munich) | Zurich

This article is written for educational purposes only and does not constitute medical advice. Always consult your healthcare provider or a qualified nutrition professional for guidance personalised to your pregnancy.