Optimum nutrition for pregnancy: Start with the basics

The quality of a mothers diet before she conceives and during pregnancy produce lifelong effects that improve her babies resilience to degenerative diseases and infection throughout their lives. In fact recent research shows that by prioritising good nutrition during pregnancy, you are supporting your babies future health and that of their children.

In short, eating a nutritious diet during pregnancy and breastfeeding can produce positive changes to your baby's physiology and gene expression (how his/her genes effect his/her health). The period from conception to six months (roughly 500 days) is the most vulnerable in a child’s life and is the period when their gene expression is the most malleable to change, therefore it is the perfect opportunity to take control over the future health of your baby. Our pregnancy diets also have an effect on our baby's food choices later in life. Research shows that babies born during times of famine are twice as likely to choose high fat foods than those who were not exposed to dietary restrictions in the womb.

Eating well throughout the four trimesters:

First trimester nutrition: You do not need to increase your total calorie intake during this time, but protein is important during all stages, especially the first trimester. However, typically protein sources such as meat and eggs may not be as appealing. If not, consider almond butter or other nut butter. Do your best to get the most nutrition possible, especially if you have morning sickness, but don’t worry too much if you are feeling sick and can’t eat the way you’d like. Standard weight gain is two to five pounds during the first trimester.

Second trimester nutrition: Protein and calcium needs increase during the second trimester. Calories increase by about 200 calories during, but its important to make those calories count by choosing nutrient dense whole foods. Blood volume increases steadily during the second and third trimester and iron becomes particularly important during this time. Standard weight gain during this trimester is about one pound per week.

Third trimester nutrition: It is of upmost importance to get enough good fats, particularly omega-3 and DHA during the third trimester. Cod liver oil is the most common way to get this, as well as other fish oils. You can also get it from pastured eggs, DHA eggs, salmon, and small amounts in plant sources. Additionally, while it is always important to watch sugar intake, the third trimester is the most important time to be diligent. It is a good idea to eat fermented foods and take a probiotic supplements. Standard weight gain during the third trimester is about one pound per week.

Total weight gain during pregnancy: A woman of average healthy weight before pregnancy will typically gain between 25 and 35 pounds during pregnancy. A woman underweight before pregnancy will gain more, and one overweight will gain less.

Blood sugar balance:

Maintaining balanced blood sugar levels is vital for the optimum health and functionality of any individual. During pregnancy your increased blood supply and elevated levels of certain hormones mean you are more likely to experience dips in blood sugar and that balance is harder to achieve. Excessive sugar in the blood can cause damage to our arteries and organs so when we consume foods containing sugar our bodies releases a hormone called insulin to pull excess glucose from the blood. The higher the sugar content, the more insulin is released causing blood sugar levels to plummet suddenly. Since we need some sugar to fuel our cells, we crave sweet treats and pick-me-ups which trigger another another spike and drop in blood sugar. The short term symptoms of blood sugar imbalance are dizziness, headaches, nausea, irritability and sugar cravings, whilst long term symptoms include anxiety, sleep problems and weight gain.

Constant fluctuations in blood sugar places unwanted stress on the pancreas and leads to the over-production of cortisol, a hormone which has a direct affect on the ageing process. Babies born to mums with poor blood sugar control are often bigger. Macrosomia is a condition where a baby grows excessively large due to a constantly high level of maternal blood sugar, generally due to gestational diabetes. This condition increases the risk of delivery complications such as shoulder distocia and cesarean section. Large babies of mothers with elevated blood sugar levels have a higher risk of childhood obesity and bigger babies are more likely to develop obesity and other health conditions in later childhood. Your midwife will monitor your blood-sugar levels during the third trimester as gestational diabetes is becoming more and more common. Follow these rules to balance your blood sugar: 

Avoid refined sugar: Simple carbohydrates (sweets, chocolate and cakes) and refined carbohydrates (white and wholewheat flour, bread, pasta and white potatoes) release sugar very quickly into the blood stream and cause it to spike. Replace these with complex carbohydrates (vegetables, fruit, brown rice, oats and quinoa) which contain fibre and release energy slowly which keeps your blood sugar balanced.

Eat regularly: Leaving large gaps between meals causes blood sugar levels to drop leaving you feeling tired and low in energy. In this state you are more likely to make poor food choices, so prevent this dip by eating three meals and two or more snacks daily. Eating a little and often will also be beneficial in the third trimester when there is not a whole lot of room in your stomach and will help to relieve heartburn.

Balance your meals: Combining carbohydrates with healthy fats and protein on the one hand and fibre on the other ensures a slower release into the blood stream. This is why an apple and a piece of chocolate may contain the same amount of sugar, but only the chocolate will spike your blood sugar. Eating a handful of nuts with your fruit or having a tablespoon of humous with your crackers will blunt the sugar spike. As a general rule all meals should contain carbs, protein and fat and snacks should contain carbs and protein. This is particularly important for breakfast which tends to be carb heavy so think natural live yogurt, nuts, seeds, fresh fruits, berries and eggs.

Avoid stimulants: Stimulants such as caffeine have the same effect as sugar on insulin release and should therefore be kept to a minimum or avoided. If you can't go without your daily coffee try taking it with half a teaspoon of cinnamon which cleverly blunts the sugar spike.

Eat fruits in their whole form rather than juicing: Fruit juice has the same effect on your blood sugar as candy. You need the fibre to bind the sugar and slow it's release into your bloodstream.

Exercise: Moderate exercise and relaxation are helpful to even out blood sugar levels. I recommend yoga, walking and swimming if you don't already have an exercise routine.

Maximise your nutrition by opting for top quality food:

Where possible buy locally grown produce as it will be fresher and have a higher nutrient content. Local produce from farmers markets is typically cheaper than supermarket produce and avoids excessive food miles whilst supporting local farmers. It is preferable to buy organic produce as this contains higher levels of antioxidants and will contribute far less to your toxic load. If you cant buy everything organic you should prioritise the dirty dozen (see resources on the website).

Grass-fed animals are free of hormones, antibiotics, pesticides like organic, and additionally, they get sunlight and access to pasture/green grass. This makes them rich in fat-soluble vitamins (A, D, E, and K) and fatty acids such as omega 3s and CLA. They are not fed corn and soy. They have less cholesterol and inflammatory fats.

The foundations of a healthy diet:

Protein: After water, protein is the most plentiful component of your body. Adequate protein supply is essential for your body to manufacture the physical structures of your baby like her hair, nails and muscles and also to produce the enzymes, hormones and growth factors vital for her development. Pregnant women should consume at least 60g protein every day and protein should make up 15-25% of your diet. Not all protein is equal though and the quality of protein is determined by the number of 'amino acids' it contains. Without getting to complicated, animal products (meat, fish, eggs etc.) contain high quality or 'complete' protein, meaning they provide all nine essential amino acids. Plant foods on the other hand (grains and legumes) contain incomplete protein meaning that they lack one or more amino acid and therefore must be eaten in combination. Eating grains and legumes together (e.g. beans on toast) provides complete protein.

Carbohydrates: Carbohydrates are essential to human nutrition because they provide the primary source of energy we need to fuel bodily functions. I just want to emphasise here that carbohydrates are not your enemy despite what popular diet models may have you believe. In pregnancy as always we should focus on complex carbohydrates and avoid or limit simple refined carbohydrates. Simple carbohydrates (sweets, chocolate and cakes) and refined carbohydrates (all flour, bread, pasta and white potatoes) provide virtually no nutrients, spike your blood sugar and cause weight gain. Whilst complex carbohydrates (vegetables, fruit, brown rice, oats and quinoa) provide plentiful nutrients and fibre and slowly release energy. Current advice is for carbohydrates to make up around a 45% of your diet during pregnancy, just make sure you choose the best sources.

Fat: Fat was demonised in the 80s but in the last few years the press seems to have caught up with the research and the nutritional headlines confirm that 'fat does not make you fat, sugar makes you fat'. That said not all fat is equal. DHA is fatty acid that makes up approximately 30 per cent of the structural fat of the brain and is key component of the heart. It accumulates both prenatally and postnatally in infant brain, eye and nervous system tissue. Developing infants cannot efficiently produce their own DHA and must obtain this vital nutrient through the placenta during pregnancy and from breast milk following birth. Increasing DHA in the diet during pregnancy and nursing significantly enhances the level of DHA available to the unborn baby and infant. Adequate consumption is particularly important during the third trimester when major brain growth occurs. Studies show that supplementation of DHA in the mother’s diet improves infant developmental outcomes, such as hand-eye coordination, motor skills and attention span. DHA has also been shown to play a part in maternal well-being and supplementation can increase the length of pregnancy by six days helping mothers carry to a healthy or full term. The western diet is typically low in DHA but sources include:

  • Oily fish, think SMASHT (salmon, mackerel, anchovies, sardines, herring and tuna).

  • Algae - micro algae is currently available in dietary supplements and fortified foods.

  • Organ meat such as liver.

  • Small amounts are found in poultry and egg yolks.

*To minimize the risk of mercury exposure, pregnant women, women who may become pregnant, nursing mothers and young children are advised to eat no more than 12 ounces of cooked fish per week and choose a variety of fish rather than a single type. Pregnant women are warned to avoid shark, swordfish and marlin, which are at the top of the food chain and therefore have higher levels of these toxins.

*Many people believe that flaxseed oil is a good source of DHA, but flaxseed oil is a dietary source of alpha-linolenic acid (ALA), a precursor of DHA. The body can make small amounts of DHA from ALA, but this process is inefficient and variable. Therefore, if you are looking for the benefits of DHA, it is best to consume it directly


Many nutrients work in synergy. For example vitamin C and is required in sufficient quantities for the absorption of iron from food and vitamin D aids in the absorption of calcium. Vitamin C and the B-complex are water soluble, meaning they are not stored in the body for long and need to be eaten regularly for a healthy pregnancy. Vitamins A, D, E and K are fat soluble and can be stored in body tissues for up to six months. Most people do not get sufficient micronutrients in their diets. The most recent UK National Diet and Nutrition Survey showed that nine in 10 women did not meet the lower reference nutrient intake (NRNI) for magnesium, iodine, zinc, calcium vitamin A or iron. Whilst supplements have their place, eating a colourful, varied and fresh diet is the most effective and enjoyable way to increase you micronutrient consumption. 

Our 'Top sources of micronutrients' table details exactly how much of each micronutrient you need during pregnancy and breastfeeding and which foods contain them. The chart is available on the website under 'resources'.

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

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