Pregnancy nutrition guide: What to eat when you’re expecting

When you’re pregnant, food can feel more important than ever, but also more confusing than ever. You want to give your baby the best possible start, but between cravings, nausea, and all the advice coming your way, it can be hard to know what truly helps. The good news is that eating well during pregnancy doesn’t have to be perfect or complicated. It’s about making nourishing choices that support both you and your baby, and being gentle with yourself along the way. This guide walks you through what to eat (and what to avoid) trimester by trimester. You’ll also find practical tips and supplement advice to help you feel confident and nourished in every stage.

Table of contents

1. The basics of pregnancy nutrition

2. What to eat in each trimester

3. Staying hydrated during pregnancy

4. Foods to avoid

5. Best supplements during pregnancy

6. Key takeaways

The basics of pregnancy nutrition: quality over quantity

One of the first things people often say when you’re pregnant is that you’re “eating for two”, right? Not exactly. Of course, you’re nourishing your baby too, but that doesn’t mean you need double portions. Most women only need around 300 to 500 extra calories per day in the second and third trimesters. It’s not about eating more, but about the quality of what you eat.

What to eat in each trimester

A balanced mix of fruit, vegetables, whole grains, lean proteins and healthy fats forms the foundation for your health and your baby’s development.

• First trimester: Nausea and food aversions can make it hard to eat well. Eat what you can and stay hydrated. Small, frequent meals and simple foods can help.

• Second trimester: Your baby’s bones are developing rapidly, so calcium becomes especially important. You’ll find it in dairy, fortified plant-based milks and leafy greens. Omega 3 fatty acids are also key for brain development. Include salmon, walnuts, flaxseeds and chia seeds.

• Third trimester: Your protein needs increase as your baby’s muscles and tissues grow. Eggs, legumes, lean meats, fish, tofu and beans help maintain your energy and prepare your body for birth and recovery.

Tip for a plant-based pregnancy: Vegetarians and vegans can have a perfectly healthy pregnancy. Just pay extra attention to iron, B12, calcium and omega 3. If you’re unsure, seek professional advice.

Staying hydrated during pregnancy

Drinking enough water is essential. It supports your increased blood volume, regulates amniotic fluid and helps with water retention, constipation and fatigue. Aim for 2 to 3 litres per day, depending on your activity level and environment.

Practical tip: Drink more in the morning and afternoon so you don’t have to get up as often during the night. Every extra minute of sleep helps.

Foods to avoid

There’s plenty you can eat, but a few foods are best left out due to safety concerns.

• Alcohol

• Raw or undercooked meat, fish or eggs

• Unpasteurised dairy

• Fish high in mercury, such as swordfish, shark or king mackerel

If you’re unsure, always check the label or ask your doctor or midwife.

Best supplements during pregnancy

Even with a balanced diet, it can be difficult to get enough of every nutrient. Supplements can help fill the gaps, but they’re a complement, not a substitute for healthy eating.

• Folic acid (folate): Prevents neural tube defects. Ideally start before conception and continue through the first trimester. Most prenatal multivitamins already contain enough folic acid.

• Iron: Only supplement if a blood test shows a deficiency. Iron supports increased blood volume. A lack of it can cause fatigue or dizziness.

• Calcium and vitamin D: Important together for strong bones for you and your baby.

• Omega 3 (DHA): Supports brain and eye development, especially if you eat less than two to three portions of oily fish per week.

• Magnesium: Can help with cramps and support sleep.

• Vitamin B12: Essential for vegetarians and vegans.

Important: Always discuss supplements with your midwife, doctor or nutritionist. Every pregnancy is unique.

Key takeaways

• Healthy eating in pregnancy is about nutrients, not double portions.

• Each trimester has its focus, but variety and hydration are always key.

• Avoid alcohol, raw products and fish high in mercury.

• Supplements can fill nutritional gaps, but food should always come first.

• Focus on progress, not perfection. Small, consistent steps make a big difference for you and your baby.

References:

Adams, J. B., Kirby, J. K., Sorensen, J. C., Pollard, E. L., & Audhya, T. (2022). Evidence based recommendations for an optimal prenatal supplement for women in the US: vitamins and related nutrients. Maternal Health, Neonatology and Perinatology, 8(1). https://doi.org/10.1186/s40748-022-00139-9

Coletta, J. M., Bell, S. J., & Roman, A. S. (2024). Omega-3 Fatty Acids and Pregnancy. Reviews in Obstetrics and Gynecology, 3(4), 163. https://pmc.ncbi.nlm.nih.gov/articles/PMC3046737/

Mayo Clinic. (2022, February 18). Pregnancy diet: Focus on These Essential Nutrients. Mayo Clinic; Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/pregnancy-nutrition/art-20045082

NHS. (2020a, December 2). Foods to avoid in pregnancy. NHS. https://www.nhs.uk/pregnancy/keeping-well/foods-to-avoid/

NHS. (2020b, December 2). Vitamins, minerals and supplements in pregnancy. Nhs.uk; NHS. https://www.nhs.uk/pregnancy/keeping-well/vitamins-supplements-and-nutrition/