Gestational diabetes and your diet

Making changes to your diet will help you manage your glucose levels and your weight, which will reduce the risk of pregnancy complications. You should be referred to a diabetes specialist dietitian who can give you advice about your diet and how to plan healthy meals.

There’s a lot of information out there about eating well. Try not to get overwhelmed because making a few simple changes can go a long way. The most important thing is to eat a healthy, balanced diet.

When you start making changes, it’s important to remember what foods to avoid during pregnancy, including some types of fish and cheese.

The glycaemic index (GI)

Your healthcare professional will talk to you about the glycaemic index (GI). This is a rating system that shows how quickly carbohydrate foods affect your glucose level.

This sounds complicated, but it’s just about replacing some foods with others to help control your glucose levels.

High GI carbohydrates raise your glucose levels quickly, which is not good if you have gestational diabetes. These foods include:

  • sugary drinks and confectionary (cake, biscuits, sweets, ice-cream etc)
  • breakfast cereals
  • fruit juices
  • white bread
  • potatoes
  • white rice

If you have gestational diabetes, low or medium GI foods are better for you because they raise your glucose levels more slowly. These include:

  • some fruit and vegetables 
  • pulses, such as chickpeas or lentils
  • wholegrain foods, such as porridge oats.

Find out more about the glycaemic index and a helpful list of foods to eat.

Eat regularly

It’s important to eat regularly – usually 3 meals a day – and avoid skipping meals.

Start with a light breakfast and aim to have regular meals, with or without healthy snacks. It is helpful to always carry healthy snacks with you, such as pieces of apple or pear. You can snack on these if you get hungry and it can also help you to avoid convenience foods like biscuits or sugary drinks.

Insulin can cause your glucose levels to fall to low (known as hypoglycaemia) so you should be given some information about hypoglycaemia.

Watch your portion sizes

How much you eat during a meal is just as important as what you eat. You may have been encouraged to have extra food or snacks because you thought that being pregnant means ‘eating for two’. Much as this might be tempting, it’s not true.

You do not need to eat any extra food in the first or second trimesters of pregnancy. In the third trimester, you may need around 200 extra calories each day, which is around half a sandwich.

Find out more about how much extra you should eat in pregnancy.

Research has also shown that the amount of carbohydrates you eat, rather than their GI rating, has the biggest influence on your glucose levels after meals. This means that even if you’re eating well, you may struggle to manage your condition if you’re eating too much.

Diabetes UK has more information about how to get your portion sizes right.

Think about what you drink

It’s important to think about what you’re drinking as well as what you’re eating. Try to avoid sugary drinks. Diet or sugar-free drinks are better than sugary versions (although these have no nutritional value). Fruit juices and smoothies can also be high in sugar, and so can drinks labelled as ‘no added sugar’. Check the nutrition label or ask your healthcare team if you’re unsure.

“I had a bizarre craving for fresh orange juice when I was pregnant. But when I was diagnosed with gestational diabetes my midwife advised me to cut it out because of the sugar content.”


As water contains no carbohydrate or calories, it is the perfect drink for pregnant women. Studies have also shown that drinking water could help control glucose levels. Drink a large glass of water with every meal and another glass in between meals.

“Water was key to keeping my glucose levels stable. I probably drank about 3 to 4 litres a day and walked for half an hour after dinner. My rule was a pint of water with every mefd and one immediately after. It worked for me and others I know.”


Find out more about how much water you should drink during pregnancy.

Look closely at low-fat options

If you often choose low-fat foods, now is the time to look a bit more closely at the ingredients. This is because:

  • low-fat options can sometimes have more sugar than the full-fat option
  • food that contain fats can slow down the release of sugar from carbohydrate, which can help stop your glucose levels from spiking.

Choose foods with natural fats, such as:

  • milk
  • olive oil
  • eggs
  • seeds
  • avocado
  • natural or Greek yoghurt

What else can I do?

You should also try to:

  • eat plenty of fruit and vegetables – aim for at least 5 portions a day
  • swap cakes and biscuits for healthier alternatives such as fruit, nuts and seeds
  • eat lean sources of protein, such as chicken, fish or lean meat
  • try lower GI options by swapping white bread for wholegrain
  • cut back on salt – too much salt is associated with high blood pressure, which can increase the risk of pregnancy complications.

Remember that everyone is different

Everyone is different and what works for some women might not work for you. For example, some women find that even healthy foods such as porridge oats, fruit or other foods increase their glucose levels. Try not to get frustrated if you find it hard to manage your glucose levels at first. You will quickly learn what works for you.

Some women who are diagnosed with gestational diabetes manage to keep their glucose levels under control using diet and exercise alone.

You may also find that your tolerance to certain foods changes during pregnancy. For example, some women may find that the same foods that worked well for them early in pregnancy cause higher glucose levels as their pregnancy progresses.

“I had to be very strict and it found it was harder to get good glucose readings the further along I was, even with the same foods that had been fine for ages.” 


“For me following a low-carb, high-fat, high-protein rule worked. I managed to avoid insulin and also lost excess weight I was carrying around for no reason. My little boy was born a healthy 6lb 10.” 


“If I had bread it would be wholegrain, and just one slice. Then fish and vegetables and some cheese. And oatcakes! Oatcakes were the things that saved me!” 


Is there anything else I can do to manage gestational diabetes?

As well as eating well, exercising can help lower your glucose levels. Walking for 30 minutes every day is recommended throughout pregnancy, and will help to lower your glucose levels.

No matter how hard they try, some women can’t control their glucose levels with diet and exercise alone. If this is the case, you may be offered medication. Medication and insulin will help but cannot replace diet and exercise, so it’s still really important that you keep your healthy habits going.

Talk to your healthcare team if you have any concerns about managing your condition. You can also talk to the Tommy’s midwives on 0800 014 7800 (Monday to Friday, 9am to 5pm), or email us at [email protected].