Managing Gestational Diabetes With Diet

By The Gut Health Clinic team

Dr Megan Rossi in a lab looking through a microscope

Gestational diabetes is a common condition whereby mothers-to-be develop high blood sugars during their pregnancy. This is usually picked up during weeks 24-28 by carrying out an oral glucose tolerance test. The great news is that it can be well managed with changes to diet, lifestyle and sometimes medication. The condition usually goes away after giving birth too. 

What causes gestational diabetes?

Firstly, it is important to highlight that gestational diabetes is often not due to any “fault” of the mother! Many women can be following a balanced lifestyle and still experience gestational diabetes. 

It often occurs due to the many changes that occur in the body during pregnancy. Namely our hormones that can make it more challenging for us to utilise a hormone called insulin properly. This hormone is responsible for helping to get the sugars (naturally contained or added) and nutrients from food into our cells for us to use. If we cannot use insulin properly then we become at an increased risk of developing insulin resistance, and some may not be able to produce enough insulin to counteract this. 

Less effective insulin means more blood remains in our blood instead of making it into our cells. This is what causes our blood sugar levels to increase. 

Can you prevent gestational diabetes?

Generally no. There are many hormonal changes that we cannot control during pregnancy. However, if we are planning to become pregnant, then we can try to reduce our risk by eating a balanced diet and engaging in regular exercise that we enjoy. If we are living with overweight and obesity, some weight loss may help to reduce our risk too and may even increase our fertility. Just be sure to regularly carry out pregnancy tests, as weight loss is not recommended during pregnancy. 

There is some emerging evidence that associates an imbalance in our gut microbiota with gestational diabetes. Whilst we don’t know what came first, the imbalance or the gestational diabetes, it also makes sense to look after our gut microbes pre-pregnancy. Assess your current diet and lifestyle: 

  • Are you getting your 30 different plants per week? 
  • Are you meeting your fibre needs of 30g per day? 
  • Are you consuming some probiotic foods such as live yoghurt and kefir? 
  • Are you getting 1-2 portions of oily fish per week?
  • Are you getting enough, good quality sleep?
  • Do you exercise regularly?

 If the answer is no to any of the above, try to gradually make shifts to your diet to change that! 

What changes can we make to our diet to manage gestational diabetes?

There is a lot that we can do with diet to try to manage our blood sugar levels and navigate gestational diabetes. This advice is different to the advice we may give for other forms of diabetes. We can think of this advice as: quality, quantity, frequency and timing, 

Quality: refers to the glycaemic index (GI). This is simply the rate at which a carbohydrate food affects our blood sugar levels. For example, sugary drinks and white bread have a high GI as they affect our blood sugar levels quickly, whilst wholegrains such as oats are lower GI as they raise our blood sugars slowly. Pick foods that contain fibre, protein and fats – as these help to improve the GI of foods. Try to avoid added sugars and be mindful of products that are also naturally high in sugar, such as juices and smoothies. Whilst GI is important, it is important to remember that we also rarely eat foods in isolation. Think about meals as whole too. For example, what can you add to the meal to make it digest more slowly?

Quantity: This refers to portion sizes. Research tells us that it is the amount of carbohydrate that we consume that has the biggest impact on our blood sugar levels after meals. Aim for 40g per meal as a ballpark amount and no or low carb snacks at no more than 10-15g carbohydrates. All carbohydrates need to be taken into account, this includes:

  • Starchy foods such as pasta, bread, rice, potatoes and cereals
  • Naturally occurring sugars in fruit (juices, smoothies, whole) and dairy 
  • Added sugars in sweets, chocolate, drinks, cakes, puddings, condiments, spreads 

Frequency: It is really important that we consume regular meals and avoid skipping meals. If we do this, then we may run the risk of running low on blood sugars for hypoglycemia. Symptoms of hypoglycemia include: hunger, sweating, irritability, shaking and confusion. If left untreated, this may cause unconsciousness. Your midwife or dietitian will be able to advise you on how to manage this. However, regular meals are one way to avoid this. Aim for three balanced meals and three snacks.

Timing: similarly to frequency, if we leave too long of a gap between meals then we may increase our risk of a low blood sugar or hypoglycaemia. This is because we should be eating less carbohydrates at our meal times to better manage our blood glucose levels. Aim to eat something every 2-3 hours.


Gestational diabetes is common. It can happen to anyone that is pregnant. There are some changes we can make prior to pregnancy that may support us, and there are plenty of changes we can make to our diet during pregnancy to help manage this condition. For some people, dietary changes may not be enough to manage their condition. Medication such as metformin may help, and has been linked to improvements in blood sugar levels and our gut microbiota. If you are struggling with dietary changes in relation to gestational diabetes or pregnancy, we would be happy to support you in the clinic!


Related articles

Follow us

The Gut Health newsletter shown on an iPad

Sign up for our free newsletter & gut health guide

Not sure where to start on your gut health transformation? Sign up for free and we’ll empower you every month with the latest educational blogs, gut-loving recipes, research updates and helpful resources delivered straight to your inbox. You’ll also receive a downloadable guide with an intro to gut science, practical advice and exclusive recipes. Lots of support and no spam.