Pregnancy is one of the most exciting — and overwhelming — periods in a woman’s life, and one of the first questions that comes to mind is: “What do I eat now?”

The answer is both simple and complex. Simple because you don’t need to “eat for two” or follow any restrictive or “magic pregnancy” diet. Complex because your nutritional needs change in every trimester, and certain nutrients play a critical role at specific stages of your baby’s development.

In this article you’ll find evidence-based, practical advice grounded in the latest clinical guidelines and current scientific research.

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How Much to Eat During Pregnancy: The Truth About Calories

The “eating for two” myth is one of the most widespread — and most misleading. Your actual energy needs increase gradually:

First Trimester (weeks 1–12): You don’t need any extra calories (unless you start your pregnancy below a healthy weight). The embryo is still very small and your body is adapting.

Second Trimester (weeks 13–26): Needs increase by roughly the equivalent of a glass of milk and half a sandwich extra, provided your activity levels stay the same.

Third Trimester (weeks 27–40): Needs increase a little more, but it’s still a modest increase — and many women reduce their activity during this trimester, so the real increase is smaller.

Throughout all trimesters, what really matters is not so much the quantity, but the quality of the foods you choose — unless your starting weight is low or there are signs that your energy intake isn’t adequate as pregnancy progresses.

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Key Nutrients by Trimester

First Trimester: The Beginning of Development

During the first trimester, the neural tube, heart and major organs of your baby are forming. This is a particularly critical nutritional phase — and it often happens before you even know you’re pregnant.

Folate / Folic Acid

Folate is the naturally occurring form of this B vitamin found in food; folic acid is the synthetic form used in supplements. It is perhaps the most important nutrient in early pregnancy — and ideally supplementation should begin before conception.

Current guidelines recommend:

• 400 mcg folic acid daily from when trying to conceive until 12 weeks.
• 5 mg daily for women at higher risk: family history of neural tube defects, diabetes, or certain medications.
• Note that if you have a BMI over 30 kg/m², current NICE guidance (2025) recommends the standard 400 mcg dose — previously 5 mg was advised for this group, but this is no longer the case unless you have other risk factors. If your doctor or midwife has advised differently, discuss it with them directly.

Folic acid significantly reduces the risk of serious neural tube defects such as spina bifida — conditions that develop in the first 28 days after conception, often before a woman knows she is pregnant. This is why starting before conception matters.

Foods rich in folate — dark green vegetables (spinach, broccoli), legumes and fortified cereals — valuable addition to your diet, but cannot replace the need for a supplement.

Iodine

Often overlooked, but critical for the development of your baby’s brain and thyroid gland. Iodine deficiency during pregnancy has been linked to lower IQ in children.

Sources: dairy products, fish, seafood, fortified plant-based milks, iodised salt. If you follow a vegetarian diet, discuss supplementation with your doctor or dietitian.

Protein

During the first trimester, protein needs increase modestly, as it’s essential for cell multiplication and tissue formation.

Good sources

• Meat, poultry, fish, eggs and dairy
• Plant-based: legumes, pulses, tofu, soya and soya products (edamame, soya milk, tempeh), Quorn, nuts and seeds

What About First Trimester Nausea?

Nausea affects a large proportion of pregnant women, especially in the early weeks. Some practical tips:

• Small and frequent meals
• Neutral flavours, cold and “dry” foods are usually better tolerated
• Good hydration (little and often, as liquids can worsen nausea — but so can dehydration)
• Ginger — consuming it through food (fresh, as a tea or spice) is considered safe and the NHS mentions it as something that may ease nausea. Ginger supplements are a different story: the UK Committee on Toxicity (COT, 2025) concluded there is insufficient safety evidence to recommend them during pregnancy. If you’re considering a supplement, speak with your doctor or midwife first.

Important: If you’re struggling with nausea, try not to worry if your diet isn’t as balanced as you’d like — this is usually temporary, and a good diet before and after this phase means the risk of nutritional deficiencies is low. If however your nausea is severe, persistent and significantly affecting your ability to eat and drink, you may be experiencing hyperemesis gravidarum. This is a medical condition that requires proper assessment and treatment — please don’t hesitate to contact your midwife or doctor.

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Second Trimester: Growth and Energy

The second trimester is usually easier than the first: nausea subsides and your energy returns. During this trimester, your baby is developing rapidly: brain, skeleton, muscles. Nutritional needs increase accordingly.

Iron

Iron starts to become particularly important from the second trimester, as your blood volume begins to increase. Iron deficiency anaemia can lead to fatigue, preterm birth and low birth weight.

Foods rich in iron:

• Animal sources (haem iron, higher absorption): red meat, chicken (thigh more than breast), fish. Note: liver is an excellent source of iron but is contraindicated in pregnancy due to its high retinol content.
• Plant sources (non-haem iron, lower absorption): legumes, spinach, pumpkin seeds, fortified cereals.

Important tip: Combine plant sources of iron with vitamin C for better absorption (e.g. lentils with lemon or parsley, spinach with pepper or tomato). Coffee and tea reduce absorption — avoid them close to iron-rich meals.

If you need an iron supplement, your doctor will advise based on blood test results.

Calcium

Your baby’s skeletal system is built with calcium. If your diet doesn’t provide enough, the baby draws it from your own stores (mainly your bones).

Good sources: pasteurised dairy (milk, yogurt, cheese), sardines with bones, almonds, dark green vegetables, fortified plant-based milks.

If you suspect your diet isn’t providing enough calcium, discuss the possibility of supplementation with your doctor or dietitian. If you’re also taking an iron supplement, take them at least 2 hours apart to optimise absorption.

Vitamin D

According to NHS and NICE guidelines, all pregnant women in the UK should take a vitamin D supplement of 10 mcg (400 IU) daily — particularly from October to March when sunlight is insufficient for the skin to produce it. If you have darker skin, spend little time outdoors, or your blood levels are low, you may need a higher dose year-round. Ideally, dosage is guided by your blood results rather than a one-size-fits-all approach.

Vitamin D works alongside calcium to support the development of your baby’s bones and teeth, and plays many other important roles in both your health and your baby’s development.

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Third Trimester: The Final Stretch

In the third trimester your baby grows rapidly and their brain enters a period of intense development. Your nutritional needs are at their highest during this stage.

Omega-3 Fatty Acids (DHA)

DHA (docosahexaenoic acid) is critical for the development of your baby’s brain and vision — particularly during the third trimester, when the brain is accumulating DHA at a rapid rate. Adequate intake during pregnancy has been linked to improved neurodevelopment and cognitive outcomes in childhood.

Oily fish is the best dietary source of DHA and a cornerstone of the Mediterranean diet. NHS guidelines recommend up to 2 portions of oily fish per week during pregnancy. Good options include salmon, sardines, mackerel and herring. Avoid fish high in mercury such as swordfish, shark and marlin.

If you don’t eat fish, speak with your doctor or dietitian about a DHA supplement — from fish oil or, if you’re vegetarian or vegan, from algae. Do make sure any supplement is specifically suitable for pregnancy: many fish oil products such as cod liver oil contain very high levels of retinol (vitamin A), which should be avoided during pregnancy.

Iron

Iron needs peak in the third trimester — your baby is building their own iron stores to fuel their first months of life. If you haven’t already had it checked, ask your doctor for blood tests. Continue with dietary iron sources as in the second trimester — and if a supplement is needed, your doctor will advise based on test results.

Protein

Protein needs are at their highest in the third trimester, supporting muscle development, the placenta and maternal tissues. Practical examples to boost your intake: eggs with sourdough, multi-seed bread and avocado, or Greek yogurt with walnuts, honey, cinnamon and chia seeds; snacks of nuts and fruit or breadsticks with cheese; lentil soup with feta and bread; dinner of ntakos (traditional Greek rusk) with pasteurised ricotta, tomato and olives.

Hydration

Blood volume and amniotic fluid both increase significantly in the third trimester, making hydration more important than ever. Aim for 8–10 glasses of fluids daily — water, herbal teas and broths all count. Staying well hydrated can also help with constipation, which is very common in the final trimester.

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The Mediterranean Diet in Pregnancy: What the Research Shows

The evidence here is compelling. A large systematic review and meta-analysis (Advances in Nutrition, 2024) found that closer adherence to the Mediterranean diet during pregnancy is associated with significantly reduced risk of:

• Gestational diabetes
• Gestational hypertension
• Pre-eclampsia
• Preterm birth
• Low birth weight

A separate review (BMJ, 2023) analysing data from over 103,000 women reported a 26% reduction in gestational diabetes and a 55% reduction in preterm birth among women following a Mediterranean dietary pattern.

Women with PCOS are at particularly elevated risk of gestational diabetes — if this applies to you, you may find it helpful to read more about nutrition and PCOS before and during pregnancy.

Mediterranean diet’s protective effect is likely driven by the diet’s combination of high fibre, antioxidants and omega-3 fatty acids alongside a low glycaemic load — all of which support metabolic health, reduce inflammation and promote healthy placental function during pregnancy.

How to Follow the Mediterranean Diet 

The Mediterranean diet doesn’t require specialist ingredients or complicated cooking. Here’s how to build it into your everyday life in the UK:

• Extra virgin olive oil: Widely available — use it as your main cooking and dressing fat
• Legumes: Lentils, chickpeas and beans are in every supermarket. Tinned versions are convenient, versatile and just as nutritious
• Frozen vegetables: Equally nutritious to fresh — a practical, affordable staple worth keeping in the freezer
• Oily fish: Salmon, tinned sardines or mackerel — all excellent sources of DHA
• Sourdough bread (ideally wholegrain or multiseed): Better nutritional profile than standard bread and a good base for balanced meals
• Greek yogurt: Higher in protein than regular yogurt, with a good probiotic profile — use it at breakfast, as a snack or as a base for sauces
• Ricotta: A mild, versatile soft cheese that works well in both sweet and savoury dishes — just confirm it’s pasteurised
• Tahini, raw unsalted nuts and seeds: Easy ways to add healthy fats, protein and minerals to breakfasts, salads and snacks

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Foods to Avoid During Pregnancy

Alcohol

There is no safe amount of alcohol during pregnancy. All international guidelines (NICE, WHO, NHS) recommend complete abstinence.

Raw or Unpasteurised Foods (listeria risk)

• Raw or undercooked eggs, and products containing them (homemade mayonnaise, some mousses and desserts)
• Raw or undercooked meat and poultry; smoked or cured meats such as salami and prosciutto; raw seafood including sushi and tartare; pâté
• Unpasteurised dairy products. Soft cheeses — including feta, ricotta, cottage cheese, cream cheese and fresh mozzarella — are safe if made from pasteurised milk, so always check the label. Avoid mould-ripened soft cheeses such as brie and camembert, and blue-veined cheeses such as stilton and gorgonzola, regardless of pasteurisation.

High Mercury Fish

Swordfish, shark, marlin, king mackerel — avoid during pregnancy. Do not exceed 4 tins of tuna per week.

Liver

Rich in iron, but contains very high levels of vitamin A (retinol) which can harm the baby in large amounts.

Caffeine

Limit to 200 mg daily (approximately 1 cup of coffee or 2 cups of tea). Avoid energy drinks or medications containing caffeine (some painkillers and cold remedies contain it). Excessive caffeine intake has been linked to lower birth weight.

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Pregnancy Supplements: What Do You Actually Need?

Folic acid: Recommended for all women before conception and until 12 weeks. Higher dose (5 mg) in cases of increased risk.

Vitamin D: Recommended for all pregnant women in the UK — particularly from October to March when sunlight levels are insufficient for the skin to synthesise it. A standard dose of 10 mcg (400 IU) daily is the baseline recommendation, but ideally your dose is guided by your blood levels rather than a blanket approach.

Iron: Only if blood tests show deficiency.

DHA/Omega-3: Not an official guideline, but if you don’t eat oily fish regularly, worth discussing with your doctor or dietitian.

Pregnancy multivitamin: Not essential if you’re eating a well-balanced diet, but can provide a useful nutritional safety net — particularly during the first trimester when nausea may limit your food choices. If you choose one, make sure it is specifically formulated for pregnancy, does not contain vitamin A (retinol), and doesn’t duplicate nutrients you’re already taking in separate supplements. Taking the same nutrient from multiple sources can lead to unintentionally high doses, which for certain nutrients carries its own risks.

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An Example Mediterranean Daily Meal Plan During Pregnancy

Breakfast: Greek yogurt with walnuts, honey and cinnamon + wholegrain sourdough bread with egg and avocado

Snack: Fruit + nuts

Lunch: Lentils + pasteurised feta + sourdough bread + salad with lemon juice + olive oil

Snack: Vegetable sticks/sesame breadsticks + hummus

Dinner: Baked salmon with steamed vegetables (broccoli, carrots) and baked sweet potato

Before bed: Glass of milk or Greek yogurt

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What About Weight Gain in Pregnancy?

Weight gain during pregnancy is normal, expected and necessary. The amount that’s right for you depends on many individual factors, but the following ranges are commonly referenced as a general guide, based on pre-pregnancy BMI:

• BMI <18.5 kg/m²: 12.5–18 kg
• BMI 18.5–24.9 kg/m²: 11.5–16 kg
• BMI 25–29.9 kg/m²: 7–11.5 kg
• BMI ≥30 kg/m²: 5–9 kg

BMI = Weight (kg) ÷ Height² (m²)

These are population-level estimates — not targets to fixate on. Weight gain in pregnancy is not linear and varies considerably from woman to woman. If you have concerns about your weight during pregnancy, speak with your midwife, doctor or a registered dietitian. Strict calorie restriction during pregnancy is never appropriate without close medical supervision.

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Do I Need Personalised Support?

Every pregnancy is different, and some situations call for more tailored nutritional guidance. This includes gestational or pre-existing diabetes, hypertension or pre-eclampsia, a multiple pregnancy, a history of difficult pregnancy or IVF, food allergies or intolerances, or following a plant-based diet.

If any of these apply to you — or if you simply want the reassurance of personalised support — I’d love to help. Take a look at the Fertility & Pregnancy Nutrition Programme or book a free discovery call to find out how we can work together. My goal is to build a practical, sustainable approach to nutrition that supports both you and your baby throughout your pregnancy journey.

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References

1. NICE Guideline NG247. Maternal and child nutrition: nutrition and weight management in pregnancy, and nutrition in children up to 5 years. National Institute for Health and Care Excellence; January 2025. https://www.nice.org.uk/guidance/ng247
2. Institute of Medicine (IOM). Weight Gain During Pregnancy: Reexamining the Guidelines. National Academies Press; 2009. https://www.ncbi.nlm.nih.gov/books/NBK32813/
3. NHS. Vitamins, supplements and nutrition in pregnancy. Last reviewed September 2023. https://www.nhs.uk/pregnancy/keeping-well/vitamins-supplements-and-nutrition/
4. WHO. Nutrition counselling during pregnancy. World Health Organization. https://www.who.int/tools/elena/interventions/nutrition-counselling-pregnancy
5. ACOG. Nutrition During Pregnancy. American College of Obstetricians and Gynecologists; June 2023. https://www.acog.org/womens-health/faqs/nutrition-during-pregnancy
6. Committee on Toxicity (COT). Statement on the Safety of Ginger Supplement Use in Pregnancy: Lay Summary. COT/2025/01. Food Standards Agency; May 2025.
7. Xu J, Wang H, Bian J, et al. Association between the Maternal Mediterranean Diet and Perinatal Outcomes: A Systematic Review and Meta-Analysis. Advances in Nutrition. 2024;15(2):100159. PMID: 38042258
8. Liyanage T, et al. Mediterranean diet and female reproductive health over lifespan: a systematic review and meta-analysis. BMJ. 2023. PMID: 37506751
9. Hart KH, et al. Diet in Pregnancy: A Review of Current Challenges and Recommendations. A British Nutrition Foundation Briefing Paper. Nutrition Bulletin. 2025. PMC12398648
10. Sherzai D, et al. A Systematic Review of Omega-3 Fatty Acid Consumption and Cognitive Outcomes in Neurodevelopment. American Journal of Lifestyle Medicine. 2023. PMC10498982
11. García-Maldonado E, et al. The Maternal Omega-3 Long-Chain Polyunsaturated Fatty Acid Concentration in Early Pregnancy and Infant Neurodevelopment: The ECLIPSES Study. Nutrients. 2024;16(5):687.
12. British Nutrition Foundation. New paper provides roadmap for optimum maternal and fetal health. July 2025. https://www.nutrition.org.uk

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Disclaimer: This article has been written for educational and informational purposes only. It does not replace personalised medical or dietetic advice. If you are pregnant or planning a pregnancy, please consult your doctor or registered dietitian.