First Trimester Nutrition: What to Eat and What to Avoid
In the first 12 weeks you need a varied, balanced diet, a daily folic acid supplement and a daily vitamin D supplement. You do not need extra calories, and you do not need a perfect menu. If nausea is limiting what you can eat, the aim is simply to get through each day, and that is usually enough.
This guide covers what UK maternity services advise, how to eat when you feel sick, a simple sample day, and the point at which one-to-one support helps.
TL;DR
- Take 400mcg of folic acid daily until week 12, plus 10mcg of vitamin D daily. A higher folic acid dose is prescribed for some women.
- There is no need to “eat for two” in the first trimester. Variety matters more than volume.
- Avoid liver and pâté, high-mercury fish, unpasteurised dairy and soft mould-ripened cheeses. Keep caffeine to 200mg a day or less.
- Nausea is common and usually settles by about week 20. If you cannot keep food or drink down, speak to your midwife or GP.
- If you have a health condition, a restrictive diet or a history of digestive problems, a personalised plan is safer than generic lists.
Table of Contents
- The two supplements that matter most
- What to eat in the first trimester
- Do you need extra calories?
- Eating when you feel sick
- Foods and drinks to avoid or limit
- Our perspective
- When personalised support helps
- FAQ
- Sources
The two supplements that matter most
Food alone does not cover everything in early pregnancy, which is why two supplements are standard advice.
Folic acid. The standard UK recommendation is 400mcg daily for women planning a pregnancy and through the first 12 weeks, to help prevent neural tube defects such as spina bifida. Women at higher risk, for example with diabetes, a BMI over 30 or a family history of neural tube defects, are advised to take 5mg, which needs a GP prescription. If you are already pregnant and have not started, begin now and tell your midwife.
Vitamin D. 10mcg daily is recommended throughout pregnancy and while breastfeeding, to support bone, teeth and muscle health. Sunlight is limited for much of the UK year, so food rarely fills the gap. You can read more about the health benefits of vitamin D, and our own guide explains what food can and cannot do for vitamin D.
If you are on a low income or receive certain benefits, you may be able to get free Healthy Start vitamins. The tablets contain folic acid, vitamin C and vitamin D.
Do not take vitamin A supplements or cod liver oil unless a healthcare professional tells you to. Vitamin A can harm your baby.
What to eat in the first trimester
NICE guidance asks professionals to tailor food advice to each person’s habits, circumstances and preferences, which is a good rule for you too (NICE NG247). The building blocks are simple:
- Fruit and vegetables: aim for plenty each day. Fresh, frozen and tinned all count.
- Starchy carbohydrates: wholegrain bread, oats, potatoes, rice and pasta. They also tend to be the easiest foods to tolerate when you feel sick.
- Protein: well-cooked meat, poultry, eggs, fish, beans, lentils, tofu and nuts.
- Dairy or fortified alternatives: for calcium and iodine.
- Iron sources: red meat, lentils, beans and green leafy vegetables, ideally with a source of vitamin C.
- Fluids: water, milk and herbal teas you tolerate.
A simple sample day
This is an illustration, not a prescription. Adapt it to what you can face.
| Meal | Example |
|---|---|
| Breakfast | Porridge with berries and a spoonful of nut butter, or toast with scrambled egg |
| Mid-morning | Dry crackers, a banana or a small yoghurt |
| Lunch | Jacket potato with beans, or a lentil and vegetable soup with wholegrain bread |
| Afternoon | Fruit and a handful of unsalted nuts |
| Dinner | Thoroughly cooked chicken or salmon, rice and steamed greens |
| Evening | Milk or a fortified plant drink with a slice of toast |
If you want a fuller checklist, we have written a practical UK guide to prenatal nutrition.
Do you need extra calories?
No. Hospital guidance is clear that you may feel hungrier but do not need to “eat for two”. Extra energy needs come later in pregnancy. In the first 12 weeks the priority is a balanced, varied diet, not larger portions.
Weight gain in the first trimester is usually small, and some women lose a little because of sickness. Do not try to lose weight during pregnancy, and do not worry if your appetite is smaller than usual for a few weeks.
Eating when you feel sick
Morning sickness is a misnomer. The RCOG explains that nausea and vomiting of pregnancy can strike at any hour, usually starts between weeks 4 and 7, and settles by 20 weeks in 9 out of 10 women.
Practical ways many women cope:
- Eat small amounts often rather than three big meals.
- Keep plain, dry carbohydrates by the bed and eat a little before you get up.
- Choose cold or room-temperature foods if cooking smells set you off.
- Sip fluids between meals rather than with them.
- Take your supplement with food, or at the time of day you feel best.
Mild to moderate sickness has no evidence of a harmful effect on the baby. But if you cannot eat or drink normally, are losing weight, or are vomiting repeatedly, contact your midwife or GP promptly. Severe sickness (hyperemesis gravidarum) affects a minority of pregnancies and needs medical care, which may include anti-sickness medication and fluids. Safe treatments exist.
Foods and drinks to avoid or limit
The NHS guidance used by hospital trusts is consistent on the main points:
- Liver and liver products such as pâté: high in vitamin A.
- Shark, swordfish and marlin: high in mercury.
- Oily fish: no more than two portions a week.
- Soft cheeses with white rinds such as Brie and Camembert, and soft blue cheeses such as Gorgonzola, unless cooked until steaming hot. Unpasteurised dairy should also be avoided because of listeria.
- Caffeine: no more than 200mg a day. A mug of instant coffee has roughly 100mg and a mug of tea about 75mg, and chocolate and energy drinks count too.
Check the label on anything you are unsure about, and ask your midwife if your diet is unusual, for example vegan or very limited by food aversions.
Our perspective
Most women who come to us in early pregnancy are not short of information. They are overwhelmed by it. Lists of rules compete with nausea, tiredness and, often, an existing condition such as a sluggish gut, thyroid trouble, prediabetes or a history of restrictive eating.
Our approach is to start with your life: what you can actually eat, your work, your cultural food, your medical background. Then we build a plan around it, so you are not forcing down foods that make you gag because a list said so. We keep the advice in line with NHS guidance, and we send you back to your midwife or GP whenever symptoms need medical care.
We also believe pregnancy nutrition should be calm. Healthy habits stick when they feel manageable, and the first trimester is a good time to set a few small ones.
— Irina
When personalised support helps
General advice is enough for many pregnancies. Individual help is worth considering if you have:
- a digestive condition such as IBS, coeliac disease or reflux;
- diabetes, prediabetes or a risk of gestational diabetes (see our gestational diabetes guide);
- a vegetarian, vegan or allergy-restricted diet;
- severe food aversions that leave you worried about what you are missing;
- chronic fatigue or a thyroid condition alongside pregnancy.
At Foodconnection our practitioner holds an MSc in Nutrition and is BANT and CNHC registered. An initial consultation of one and a half hours with written personalised recommendations costs £150, and a follow-up within 8 weeks is £120. Our 12 weeks of dedicated support costs £250, which covers roughly the whole first trimester. You can see everything on our prices page, or read about our nutrition services, which include pregnancy yoga.
FAQ
What should I eat if I can only manage plain foods?
Plain toast, crackers, potatoes, rice, bananas and yoghurt are all fine for a few weeks. Add protein and fruit or vegetables whenever you feel able, and keep taking your supplements. If you cannot keep anything down, speak to your midwife or GP.
Do I need to cut out caffeine completely?
No. Current UK advice is to keep caffeine to 200mg a day or less, counting tea, coffee, chocolate and energy drinks. Switching to decaffeinated versions for some of your drinks makes this easy.
Can I take a normal multivitamin?
Check the label first. Many general multivitamins contain vitamin A, which you should avoid in pregnancy. A product made for pregnancy, or Healthy Start vitamins if you are eligible, is a safer choice. Ask a pharmacist or your midwife if unsure.
Is a first trimester meal plan necessary?
Not for everyone. A flexible pattern of regular meals and snacks, like the sample day above, works for most women. If you have a medical condition or specific dietary needs, a plan built for you is more reliable.
Sources
- NHS Royal Devon: vitamins and supplements during pregnancy and breastfeeding
- Healthy Start: getting vitamins
- NICE NG247: maternal and child nutrition
- Milton Keynes University Hospital: having a healthy pregnancy
- RCOG: pregnancy sickness
- Keeping healthy during pregnancy (NHS trust leaflet)