Protein helps maintain good blood glucose levels and is a very important part of a good gestational diabetes diet, therefore many women look for products high in protein to add into the diet to increase the amount of protein being consumed.

Protein positively affects the growth of fetal tissue, including the brain. It also helps your breast and uterine tissue to grow during pregnancy, and it plays a role in your increasing blood supply.

Pregnancy Nutrition: Food Groups, American Pregnancy Association
protein rich foods

The delayed spike in blood sugar levels from protein

While a higher protein diet helps to pair carbs, reducing spikes in blood sugar levels, it is important to balance small servings of unrefined complex carbs with protein, natural fats and plenty of green salad or vegetables to achieve this.

Eating very high protein alone can cause delayed spikes in blood sugar levels, as around 50% of protein turns into glucose in 2 – 4 hours.

If you notice that your blood sugar levels are within target one-hour post-meals, but are raising after two hours, or you are seeing high before meal blood sugar levels, this could suggest you are consuming too much protein and the spike in levels is being delayed.

Macronutrients impact on blood glucose

High-protein diets have become more popular over the last few years, with many companies and stores jumping on this extremely lucrative market.

The global protein market size was accounted at USD 10.37 billion in 2022 and it is expected to reach around USD 23.34 billion by 2032.

Precedence Research [accessed 03/03/2023]

This means that protein enriched foods and drinks are now much easier to find, with most stores, even petrol stations, and coffee shops offering high protein snacks, foods and drinks.

There are a few things to watch out for with these types of products:

A high protein product does not mean it is low-carb or low in sugars. Many protein supplements and enriched products are marketed to the fitness industry for bodybuilders and people looking to build muscle. Therefore they are not focusing on calorie control or weightloss. Many products may help bulk or give more energy for working out, meaning they may be high in carbs for this purpose and therefore not good for blood sugar levels.

There is a lucrative market for high-protein products meaning many companies have brought out higher protein versions of regular products but have only added a very small amount of extra protein. Yet they have marketed the product with bold writing, stating it is HIGH PROTEIN (as it is higher in protein than their regular version). The amount of protein can be minimal and could be achieved by adding a teaspoon of chia seeds to the regular version or eating a handful of nuts alongside the product.

The high-protein market has driven companies to advertise some convenience foods such as ready meals, pizzas etc. as high protein. Yet, they have the same amount of protein as other regular products, which aren’t highlighted as high-protein yet can cost significantly more. Check the ingredients, check the labels and don’t be fooled into thinking a product marketed as high protein is any better than a regular version that does not mention protein! An extra sprinkle of cheese on a thin-crust store-bought pizza may contain the same amount of protein as a Protein Pizza at double the cost.

Some products will state an amount of protein in big, bold letters on the front of their product, but when you read the fine print, the amount of protein is for the whole packet, not one serving. Therefore this product is not particaulry high in protein unless you consume the whole pack, which means a high amount of carbs are also being consumed simultaneously.

Take a walk down the yoghurt aisle, and you will now find an abundance of protein yoghurts, puddings and mousses. These yogurts are often quark (cheese) and are not actually yogurt. They can be high in carbs (sugar), with added carbs in the form of granola, fruits, compote, flavourings, etc., and often contain additional artificial sweeteners. Some are milk yoghurt with added milk and soya protein to increase protein content.

Many protein puddings are made from milk, milk proteins, starches, with added flavourings, thickeners, some contain gelatine and the majority contain artificial sweeteners such as Acesulfame K and Sucralose which can raise blood sugar levels and cause a nasty bitter aftertaste.

These protein puddings may offer a quick, sweet fix, but some have an awful artificial taste and may still raise blood sugar levels.

High artificial sweetener consumption in pregnancy has been found to cause adverse effects, so it is essential to check which sweeteners are being used and think about the amount being consumed on a regular basis. You can read more about the effects of artificial sweeteners in pregnancy here.

Effects of consuming sugars and alternative sweeteners during pregnancy on maternal and child health: evidence for a secondhand sugar effect, Published online by Cambridge University Press:  03 December 2018

Products marketed as high protein are often much more expensive than products not highlighted and marketed as high protein. This may not be a cause of concern for some, but weekly I see posts on my Facebook group where members are struggling with the cost of a GD-diet. Therefore, you must note that you do not need to purchase these kinds of products to follow a good GD diet. There are many sources of real whole food containing good amounts of protein that can be purchased and are much more affordable.

Evidence-based research on high protein supplementation in pregnancy

Are high protein-enriched foods, drinks, and protein supplements something we should add to a GD diet, and what impact can a high-protein-supplemented diet have?

protein supplements

Balanced energy and protein supplementation seems to improve fetal growth, and may reduce the risk of stillbirth and infants born small‐for‐gestational age. High‐protein supplementation does not seem to be beneficial and may be harmful to the fetus. Balanced‐protein supplementation alone had no significant effects on perinatal outcomes.

Antenatal dietary education and supplementation to increase energy and protein intake, June 2015, Cochrane Systematic Review 

In two trials (529 women), high‐protein supplementation was associated with a small, non‐significant increase in maternal weight gain but a non‐significant reduction in mean birthweight, a significantly increased risk of SGA birth, and a non‐significantly increased risk of neonatal death. In three trials, involving 966 women, isocaloric protein supplementation was also associated with an increased risk of SGA birth.

Energy and protein intake in pregnancy, October 2003, Cochrane Systematic Review 

Protein supplementation during pregnancy has also been debated because there might be competition among amino acids, which might negatively affect fetal growth, as shown in animal models.

In a randomized controlled trial in low-socioeconomic-status pregnant women living in New York, negative pregnancy outcomes (increased risk of infants born small-for-gestational age) were reported with high-protein supplements (providing >34% of energy). But several other studies in which the protein supplements were provided as food and conducted in the presence of adequate energy, showed a significant reduction in the risk of small-for-gestational age infants, suggesting prevention of intrauterine growth restriction. Thus, as discussed extensively by Imdad and Bhutta, protein supplementation during pregnancy must be a balanced protein supplement (<25% of the total energy content) to ensure reduction in risk of small-for-gestational age infants. Furthermore, earlier studies from the Montreal Diet Dispensary found that pregnant women from lower socioeconomic groups who received an intervention with individualized nutritional rehabilitation and consumed ~100 g protein/d had the best pregnancy outcome as measured by reduced incidence of low birth weight.

protein supplementation during pregnancy should be in the form of food supplements, balanced (within 25% of total energy), and, as stated earlier by Prentice et al., with a view to prevent intrauterine growth restriction and not as a goal to increase birth weight.

The average daily protein intakes would be ~79 g/d (~14% of calories) during early gestation and 108 g/d (~17% of calories) during late gestation for normally nourished women gaining gestational body weight within recommendations.

More studies are also necessary to confirm the positive effect of food-based protein supplements during pregnancy, with a focus on preventing intrauterine growth restriction, to ensure that protein supplements are always as a balanced protein-energy supplement (<25% of total energy content).

Protein and Amino Acid Requirements during Pregnancy, July 2016, American Society for Nutrition

We showed that a moderate protein intake (18–20%E) may support women to consume the largest variety of nutrients across all food groups. However, the findings from Maslova et al. suggest that if this moderate protein intake is made up largely of animal protein it could unfavorably increase offspring BMI in adult life. Antenatal nutritional advice with the aim of moderating energy and optimizing protein intake has been effective in reducing the risk of preterm birth and stillbirth and in increasing head circumference at birth.

High-protein diets during pregnancy: healthful or harmful for offspring?, September 2014, The American Journal of Clinical Nutrition

Protein-rich, low-carb REAL foods

Here is a list of protein-rich foods that are lower in carbohydrates and could be incorporated into a GD diet instead of using protein supplements and protein-enriched foods.

There are other foods which contain good amounts of protein such as beans, pulses, lentils and oats etc. however these sources of protein are higher in carbohydrates and so need to be thought of as a carb on the plate.

  • Eggs (one medium egg contains around 6g of protein)
  • Milk (200ml of whole milk contains around 7g of protein)
  • Greek Yogurt (100g serving contains around 9g of protein)
  • Cottage cheese (100g serving contains around 9g of protein)
  • Cheddar (50g serving contains around 12g of protein)
  • Babybel cheese (1 mini Babybel contains 4.5g of protein)
  • Salmon fillet (100g of salmon contains around 25g of protein)
  • Tuna ( ½ of a can/50g contains around 13g of protein)
  • Cod (100g serving contains around 16g of protein)
  • Prawns (100g serving contains around 13g of protein)
  • Chicken breast (150g breast fillet contains around 36g of protein)
  • Turkey (100g serving contains around 30g of protein)
  • Beef, Pork, Lamb (100g serving contains around 20g of protein)
  • Bacon (2 rashers of back bacon contains around 13g of protein)
  • Pork rinds/scratchings (25g bag contains around 18g of protein)
  • Seitan (100g serving contains around 75g of protein)
  • Tofu (100g serving contains around 12g protein)
  • Tempeh (100g serving contains around 19g of protein)
  • Quorn pieces (100g serving contains around 14g of protein)
  • Soya Milk (200ml contains around 10g of protein)
  • Soya Yogurt (100g serving contains around 4g of protein)
  • Nuts (25g serving contains around 6g of protein)
  • Peanut butter (30g spoonful contains around 8g of protein)
  • Chia seeds (1 tablespoon contains around 6g of protein)
  • Flaxseed (1 tablespoon contains around 2g of protein)
  • Edamame beans (50g serving contains around 6g of protein)
  • Broccoli & Cauliflower (100g serving contains around 4g of protein)
  • Brussels Sprouts (100g serving contains around 3.5g of protein)

Protein Bars

Protein bars are something that many find helpful as a snack on a gestational diabetes diet, or some like to use them as a cereal substitute in the mornings served with milk and cream as they can no longer tolerate breakfast cereals.

Trek Protein Nut Bars

Many individually sold protein bars contain very high amounts of protein (20-30g per bar) as they are fortified with protein supplements and are aimed at sports enthusiasts who are trying to build muscle etc.

These protein bars can be extremely expensive at a couple of pounds each when you could get a more suitable protein bar in a multi-pack made from nuts and seeds.

Other protein bars may be labelled as ‘high protein’ when in fact they are not much higher in protein than other snack bars and can contain relatively high amounts of carbs in the form of syrups, fruits, honey etc. and artificial sweeteners meaning they can contain more sugar than a chocolate bar! Therefore, they are not a good choice as they will spike blood glucose levels.

Below is a comparison table of widely found protein bars. The ones listed in green are better ones to try. Amber shows some that may be tolerable to some, and the ones in red contain much less protein and much more carbs, making them ones to avoid.

 Protein (g)Fat (g)Carbs (g)
TREK Protein Nut Bar Blueberry & Pumpkin Seed 40g10.615.56.2
TREK Protein Nut Bar Coconut & Raspberry 40g10.215.46.5
TREK Protein Nut Bar Chocolate & Sea Salt 40g10.314.96.9
TREK Protein Nut Bar Chocolate & Orange 40g10.514.97.0
Aldi Harvest Morn Protein Bar 30g8.17.17.4
Yes! Tempting Dark Choc, Sea Salt & Almond Nut Bars 35g7.113.37.5
Nature Valley Protein Coconut & Nuts Bar 40g10.312.28.8
Yes! Dark Chocolate, Banana & Pecan Fruit & Nut Snack Bars 35g5.811.38.8
Yes! Sumptuous Cranberry & Dark Choc Nut Bars 35g7.111.98.9
Nature Valley Protein Salted Caramel Nut Bar 40g10.312.39.4
Nature Valley Protein Peanut & Chocolate Bar 40g10.212.09.6
Eat Natural Protein Packed with Peanuts & Chocolate 45g10.213.714.6
Graze Peanut Butter & Chocolate Protein Bites 30g4.78.712.0
Special K Protein Coconut, Cocoa & Cashew Bars 28g6.44.512.0
Special K Protein Blackcurrant & Pumpkin Seed Bars 28g6.44.513.0
ASDA Protein Raisin & Hazelnut Cereal Bars 28g4.74.813.0
ASDA Peanut Butter Fruit & Peanut Bars 35g4.25.814.0
ASDA Cinnamon Apple Fruit & Peanut Bars 35g4.15.714.0
Alpen Protein Bar Chocolate 34g6.53.415.0
ASDA Protein Cocoa & Peanut Cereal Bar 28g4.04.615.0
Cadbury Peanut Protein Brunch Bar 32g4.77.816.0
Alpen Protein Bar Berries & Yogurt 34g6.52.516.0
Trek Cocoa Oat Protein Flapjack Bar 40g7.48.817.6
Cadbury’s Brunch Cranberry & Nut Protein Bar 32g4.46.118.0
Nairn’s Gluten Free Oat Bar Mixed Seeds & Protein 40g5.47.418.9
Nature Valley Nut Butter Peanut Biscuits 38g4.410.519.7
Nature Valley Crunchy Peanut Butter Cereal Bar 42g4.39.025.1
Nature Valley Crunchy Oats & Dark Chocolate Cereal Bar 42g3.78.425.2
Nature Valley Crunchy Oats & Honey Cereal Bar 42g3.47.227.1
Nature Valley Crunchy Canadian Maple Syrup Cereal Bar 42g3.37.227.1

Don’t think of a protein bar as a source of protein alone

The protein bars listed above in green and amber should not be considered a protein source alone, as many still contain the equivalent of around 2 tsp of sugar. Therefore, it is best always to pair protein bars with natural fats.

Nature Valley protein bar