Gestational Diabetes Diet: What to Eat and What to Avoid

Medically reviewed content. Last updated: April 2026.

If you have been diagnosed with gestational diabetes, diet is the first and most important step in managing your blood sugar levels. For most people, the right eating pattern is enough to keep levels within a safe range without medication. This guide explains what works, what to limit, and how to build meals that keep you and your baby healthy.

What is gestational diabetes?

Gestational diabetes (GD) develops during pregnancy when your body cannot produce enough insulin to meet the increased demands. It affects around 4 to 5% of pregnancies in the UK and is usually diagnosed through a glucose tolerance test (GTT) between 24 and 28 weeks.

The goal of management is to keep your blood sugar levels within target ranges. Your diabetes team will give you a blood glucose monitor and specific targets, which are typically below 5.3 mmol/L fasting (before breakfast) and below 7.8 mmol/L one hour after meals, or below 6.4 mmol/L two hours after meals.

The core principles of a GD diet

Managing gestational diabetes through diet is not about cutting out food groups or eating less. It is about choosing foods that release energy slowly and steadily, avoiding large spikes in blood sugar.

1. Choose low glycaemic index (GI) carbohydrates

Carbohydrates have the biggest effect on blood sugar. Low-GI carbs are digested more slowly, causing a gentler rise in blood sugar.

Good choices: Wholegrain bread (seeded or granary), basmati rice, sweet potatoes, oats and porridge, whole wheat pasta, quinoa, lentils and beans, most fruits in moderate portions.

Limit: White bread, white rice, sugary cereals, instant oats, mashed potatoes, white pasta.

You do not need to avoid carbohydrates entirely. They are an important energy source. The key is choosing the right type and spreading them evenly across your meals.

2. Pair carbs with protein and healthy fats

Eating protein or fat alongside carbohydrates slows digestion and reduces blood sugar spikes. For example, toast with peanut butter will cause a smaller spike than toast with jam. Porridge with nuts and seeds will have a gentler effect than porridge with honey.

Good protein sources: Eggs, chicken, fish, tofu, Greek yoghurt, cheese, nuts, lentils, beans.

Good fat sources: Avocado, olive oil, nuts, seeds, oily fish.

3. Eat smaller, more frequent meals

Rather than three large meals, aim for three moderate meals plus two to three snacks throughout the day. This keeps blood sugar levels more stable and prevents the large spikes that can come from eating a big meal in one sitting.

A typical daily pattern might look like: breakfast, mid-morning snack, lunch, afternoon snack, dinner, optional evening snack.

4. Watch portion sizes of carbohydrates

You do not need to cut carbs out, but keeping portions moderate at each sitting helps. A rough guide is to fill a quarter of your plate with carbohydrates, a quarter with protein, and half with vegetables or salad.

5. Be careful with breakfast

Blood sugar is often hardest to control in the morning because of the natural rise in hormones (the "dawn phenomenon"). Many people with GD find that their breakfast needs to be lower in carbohydrates and higher in protein than other meals.

Breakfast ideas that work well: Eggs on one slice of wholegrain toast, Greek yoghurt with a small handful of berries and nuts, porridge made with milk (not water) topped with seeds and a few berries, cheese and tomato on one slice of seeded bread.

Breakfasts to avoid: Large bowls of cereal (especially sugary types), toast with jam or marmalade, fruit juice, smoothies with lots of fruit, pastries and croissants.

What to limit or avoid

Sugary drinks and fruit juice

These cause rapid, large blood sugar spikes. Swap fruit juice for whole fruit (the fibre slows absorption) and sugary drinks for water, sugar-free squash, or herbal tea.

Sweets, chocolate, cakes, and biscuits

These are high in sugar and will spike your levels. You do not have to avoid them completely for the entire pregnancy, but they should be occasional treats rather than daily staples. When you do have something sweet, eat it after a meal rather than on its own, as the protein and fat from the meal will slow the sugar absorption.

White refined carbohydrates

White bread, white rice, and regular pasta cause faster blood sugar rises than wholegrain alternatives. Swapping to wholegrain versions is one of the simplest and most effective changes.

Large portions of fruit

Fruit is nutritious, but it contains natural sugar. Stick to one to two portions at a time and pair fruit with protein (apple with cheese, berries with yoghurt) to slow the blood sugar response. Tropical fruits (mango, pineapple, grapes) tend to be higher in sugar than berries, apples, and pears.

Processed foods

Many processed foods contain hidden sugars and refined carbohydrates. Cooking from scratch where possible gives you more control over ingredients.

Sample meal ideas

Breakfast options:

• Two scrambled eggs on one slice of seeded toast
• Porridge with a tablespoon of almond butter and a small handful of blueberries
• Full-fat Greek yoghurt with walnuts and a few raspberries

Lunch options:

• Chicken and avocado salad with a small wholegrain wrap
• Lentil soup with a slice of granary bread and cheese
• Tuna and bean salad with olive oil dressing

Dinner options:

• Grilled salmon with roasted sweet potato and green vegetables
• Chicken stir-fry with vegetables and a small portion of basmati rice
• Bean and vegetable chilli with a small portion of brown rice and a dollop of Greek yoghurt

Snack ideas:

• A handful of nuts and seeds
• Apple slices with peanut butter
• Cheese and oatcakes
• Hummus with vegetable sticks
• A small pot of full-fat yoghurt
• A boiled egg

What if diet alone is not enough?

For around 10 to 20% of people with gestational diabetes, diet and lifestyle changes alone are not enough to keep blood sugar within target. If your readings remain consistently above target despite following dietary advice, your diabetes team may recommend medication.

Metformin is the most commonly prescribed first-line medication. It helps your body use insulin more effectively. It is taken as tablets with meals.

Insulin injections may be needed if metformin alone is not sufficient, or if your blood sugar levels are very high at diagnosis. Your diabetes team will teach you how to inject and adjust your dose.

Neither metformin nor insulin will harm your baby. The priority is keeping your blood sugar levels within a safe range, and medication is a tool to achieve that, not a failure of willpower.

What about after birth?

Gestational diabetes usually resolves after delivery. Your blood sugar will be checked after birth and again at your six-week postnatal check. You will also be offered an annual HbA1c blood test going forward, because having had GD increases your lifetime risk of developing type 2 diabetes (around 50% within 10 years without lifestyle changes).

The good news is that the same dietary principles that help manage GD, choosing lower-GI carbs, eating balanced meals, staying active, and maintaining a healthy weight, significantly reduce this future risk.

Key takeaways

• Diet is the cornerstone of gestational diabetes management, and most people can control their levels through food choices alone
• Choose low-GI carbohydrates and pair them with protein and healthy fats at every meal
• Eat smaller, more frequent meals rather than three large ones
• Breakfast is often the hardest meal to get right, so keep it high in protein and low in carbs
• Limit sugary drinks, sweets, white refined carbs, and large portions of fruit
• If diet alone is not enough, metformin or insulin are safe and effective options
• GD usually resolves after birth, but maintaining healthy habits reduces your future risk of type 2 diabetes

Sources

• NHS. Gestational diabetes. nhs.uk
• NICE Guideline NG3. Diabetes in pregnancy. 2015, updated 2020
• Diabetes UK. Gestational diabetes: food and keeping active. diabetes.org.uk
• RCOG. Gestational diabetes. Patient information. 2023
• British Dietetic Association. Gestational diabetes diet sheet. bda.uk.com