Gestational diabetes and your diet

If you have gestational diabetes, your diet will become an important part of managing your condition and keeping your pregnancy safe.

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

If you have gestational diabetes, you need to limit the amount of sugary foods and drinks you have. These foods raise your blood sugar levels very quickly. You will be shown how to monitor your blood glucose levels and, as you go on, you will see which foods are raising these levels too high.

You are also likely to find that your tolerance to certain foods could change during pregnancy. Some women can start out eating cereal without a problem for example, but as their pregnancy gets on they find that the same food causes a blood sugar spike.

‘I was diet controlled all the way through but I had to be very strict and it found it was harder to get good blood sugar reading the further along I was, even with the same foods that had been fine for ages.’ Isabella

‘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.’ Maria

Carbohydrates and blood sugar levels

It’s helpful to understand how carbohydrates (carbs) work. Carbohydrates are the sugars, starches and fibres found in fruits, grains, vegetables and milk products. They are the body's main source of energy.

Some carbs release sugar into the bloodstream faster than others. These are called ‘simple’ carbs. This raises your blood sugar levels. Others release sugar more slowly. These are called ‘complex’ or ‘starchy’ carbs.

The glycaemic index shows which foods release sugar quickly and which ones don't.

  • High glycaemic foods = release sugar quickly
  • Low to moderate glycaemic index = release sugar more slowly

 Read more about the glycaemic index and find a list of foods that have a low glycaemic index (low GI) here.

Simple carbohydrates include sweet foods such as sugar, honey and natural sugars that occur in foods like milk and fruit. Sugar is also added to many foods, from cakes and chocolate to jars of cooking sauce. Some of these foods release sugars instantly into your bloodstream, causing it to spike suddenly.

Starchy carbohydrates include foods such as pasta, noodles, rice, couscous potatoes and bread. They are broken down before the sugars are released into your bloodstream, which means that the process happens more slowly. Wholegrain versions are better than white/processed versions, as they are digested even slower because of the extra fibre.

The healthiest carbs include wholegrains, pulses (beans and lentils) and vegetables, and some dairy foods. When choosing fruit, look for ones that are grown in this part of the world, such as apples and pears. They tend to have less sugar than tropical fruit.

Eat little and often

The other thing you can do to keep your blood glucose levels fairly constant is to eat little and often.

Start with a good breakfast and top up through the day with regular meals, with or without snacks. If you treat your diabetes with insulin or glibenclamide, it helpful to always carry healthy snacks with you, such some pieces of apple or pear, so you can have this if you think your blood sugar is dropping. Having a healthy snack means you can avoid becoming too hungry or having to rely on convenience foods like biscuits or sugary drinks.

Watch portion sizes

The amount you eat during a meal is as important as what you eat. Even if you choose a very low glycaemic food, if you eat too much of it, it will cause blood sugar to spike.

These are examples from Diabetes UK of portions you should be having:

  • Cooked rice = 2 heaped tablespoons
  • Breakfast cereal = 3 tablespoons
  • Boiled pasta or cooked noodles = 3 heaped tablespoons
  • Hard cheese = small matchbox
  • Cooked lean meat (eg chicken, beef or pork) = deck of cards
  • Beans and pulses (eg red kidney beans, butter beans, chickpeas or lentils) = 4 tablespoons
  • Nuts or peanut butter (unsalted) = 2 level tablespoons

Using smaller plates helps with portion sizes.

Everyone is different

Everyone is different and what works for some women might not work for you. Some women find that porridge, fruit or other foods, even though they are generally recommended, do not work for them as they increase their blood glucose levels. If you find it hard to control your blood glucose levels, try not to get frustrated. Over time, you will learn what works for you.

"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!" Michelle

Look closer at low-fat options

If you have spent your life choosing low-fat foods now is the time to look a bit more closely at the ingredients, for two reasons:

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

Choose foods with natural fats, such as whole milk, cheese nuts, olive oil, eggs, seeds or avocado, and remember to watch portion sizes.

Drink water

As well as keeping you hydrated, drinking plenty of water can help stabilise your blood sugar levels, by helping flush the sugar out through your system. Drink a large glass of water with every meal and another one 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 post evening meal and generally kept active. My rule was a pint of water with every meal and one immediately after.  It worked for me and others I know.’ Maria

Tips for eating well with gestational diabetes

  1. Eat regular meals.
  2. Watch your portion sizes, there's no need to 'eat for two'. Portion size will have the biggest effect on your blood glucose level.
  3. Include carbohydrates but look for low GI options and don't have too much.
  4. Get your five vegetables a day for vitamins, minerals and fibre for you and your baby.
  5. Cut back on salt, too much salt is associated with high blood pressure, which increases the risk of diabetes complications.
  6. Remember that drinks count too. Stick to water or sugar-free drinks.
  7. Don't look for special diet foods. Diabetes UK says they are expensive and can contain as much fat and calories as ordinary versions, and they can also have a laxative effect.

Read more:

Understanding the glycaemic index

Meal ideas with gestational diabetes

Gestational diabetes and managing your weight

Read more about diet and exercise with gestational diabetes

Read more about treatment for gestational diabetes


  1. Diabetes UK. Portion sizes and diabetes. (accessed 17/07/2018)

  2. Diabetes UK. 10 ways to eat well with diabetes. (accessed 17/07/2018) 

  3. Roussel R, Fezeu L et al (2011) Low Water Intake and Risk for New-Onset Hyperglycemia. Diabetes Care. 2011 Dec;34(12):2551-4. doi: 10.2337/dc11-0652. Epub 2011 Oct 12.
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    Last reviewed on July 17th, 2018. Next review date July 17th, 2021.

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    Please note that these comments are monitored but not answered by Tommy’s. Please call your GP or maternity unit if you have concerns about your health or your baby’s health.
    • By Anonymous (not verified) on 7 Dec 2017 - 08:50

      Thanks for this awesome article :) Gestational diabetes is a nightmare. I would like to ask you guys have anyone ever used this online blood glucose levels chart and what is your opinion on that?

    • By Midwife @Tommys on 7 Dec 2017 - 14:02

      Hi, Thank you for your comment.

      We would recommend that any women who has been diagnosed with gestational diabetes to go with the levels that the diabetes team at their local hospital has given them. You should have a specialist diabetic team that you see on a regular basis and they can monitor if your blood sugars are well controlled. If you are concerned about this then please contact your diabetes midwife or local maternity unit for further advice. Take Care, Tommy's Midwives x

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