Rhubarb Crumble

Tart, but sweet enough as a delicious fruity pudding, this rhubarb crumble is definite comfort food eating but without any added sugar
low carb rhubarb crumble and double cream in a bowl

Whilst fruit is packed full of goodness in the form of vitamins, minerals, fibre and phytonutrients it is a also packed with fructose, natural sugars. Most will know from testing their blood glucose levels, that fructose can spike levels rapidly.

For this reason, fruit can be really difficult to tolerate. Even more so if blended, blitzed or cooked as it has already been broken down meaning the body can more easily absorb the sugar.

This means that any cooked fruit must be very low in fructose and should be sharp, more tart fruit which will not raise blood glucose levels too high, too rapidly. It should also be paired with fats and protein.

Whilst I replace what fruit I would normally eat with plenty of vegetables and salads, fruit becomes one of my main cravings whilst pregnant as it is something that I struggle to tolerate. I try to stick to lower GI fruits, but as my pregnancy progresses my tolerance to even things like kiwi and berries becomes worse. For this reason I was very dubious about trying a cooked fruit dessert.

However, after moving back into the countryside and whilst picking out new fruit trees and shrubs to plant I came across the rhubarb plants and it hit me that rhubarb is one of my favourite cooked fruits and is very sharp. Looking up the carb content and GI value I found too many differing answers and so being pregnant with my usual high insulin resistance, I figured the best thing to do was to just cook it and try to make a low carb rhubarb crumble!

Rhubarb is a rich source of antioxidants and fibre.

Here are the results of my testing at before eating (4.4mmol/L), then at 15, 30, 60, 90 and 120 minutes after eating. I have tested so frequently (spike tested) to catch any high spikes and to give a better idea of how the crumble has truly affected my blood glucose levels.

To give you an example of my insulin resistance, I have taken no insulin when eating this and I currently take around 35 units of rapid acting insulin with meals (26 weeks pregnant at this time and take 70 units of slow acting insulin before bed and between 20 – 35 units of rapid acting insulin with meals).

low carb rhubarb crumble and double cream in a bowl

Rhubarb Crumble

Tart, but sweet enough as a delicious fruity pudding, this rhubarb crumble is definite comfort food eating but without any added sugar
4.34 from 3 votes
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Course: Desserts, Snacks
Cuisine: British
Diet: Diabetic, Gluten Free, Vegetarian
Keyword: crumble, pudding, rhubarb
Free or Subscription Recipe: Free Recipe
Free from: coconut, eggs, gluten
Prep Time: 10 minutes
Cook Time: 20 minutes
Total Time: 30 minutes
Servings: 4 servings
Calories: 92kcal
Author: Jo Paterson


Stewed rhubarb

  • 400 grams rhubarb stalks washed and chopped
  • 2 tbsp water
  • 2 tbsp xylitol or erythritol sweetener

Crumble topping (with nuts)

  • 1 tbsp ground almonds
  • 1 tbsp flaked almonds
  • 1 tbsp rolled porridge oats
  • 1 tbsp chopped nuts (I used hazelnuts)
  • 1 tsp ground flaxseed
  • 1 tbsp xylitol or erythritol sweetener
  • 2 drops vanilla extract
  • ½ tsp ground cinnamon (optional)
  • 1 tbsp unsalted butter cold (fridge temp works best)


Stewed rhubarb

  • Cut the rhubarb stalks into 2 cm pieces (discarding both ends) and add to a non stick saucepan
  • Wash the cut rhubarb in water (in the saucepan as this extra water helps the cooking process), roughly drain and add another 2 tbsp of water for cooking
  • Cook on high until the rhubarb starts bubbling/boiling, stir and then turn the temperature down to a simmer for for 5 minutes until the rhubarb is cooked but still holding it's shape
  • Sprinkle in the 2 tbsp of xylitol, stir through and add more to taste if required, then set the cooked rhubarb aside

Crumble topping (with nuts)

  • Preheat an oven to 180°c
  • Add all the dry ingredients to a bowl and mix well
  • Add the vanilla extract and chunks of cold butter, then rub the butter into the dry ingredients between fingers to create a crumble
  • Butter the bottom of ramekins or crumble dish, add the stewed rhubarb and sprinkle over the crumble topping
  • Place in the middle of the oven and cook for 10 minutes or until the topping is golden and the rhubarb is starting to bubble at the edges
  • Serve with double cream, clotted cream, full fat Greek yoghurt, full fat crème fraîche, real fresh custard or a well tolerated vanilla ice cream. More xylitol can be sprinkled on top if you feel the crumble is not sweet enough


A popular choice to add to stewed rhubarb is ginger and so fresh or dried ground ginger would work well if you like it, but avoid stem ginger due to the high sugar content.
Avoid adding dried fruits as these are very high in natural sugar! If changing the fruit to something like apple, or berries then be sure to test levels regularly to see how the cooked fruit affects you. More information on this can be found on our spike testing page. For a nut free version of this crumble, please see the nut free rhubarb crumble recipe.
The main two natural sweeteners I use in my recipes are xylitol and erythritol. The brand of xylitol that I use and is most widely available in larger supermarkets is Total Sweet. To find a local stockist, please check this link. It is important to note that xylitol, although a natural sweetener, is highly toxic to dogs, so no sharing your GD treats with your furry friends! If you struggle with IBS you may find you are sensitive to xylitol, in which case erythritol is a better choice. I use NKD Living powdered erythritol. 
total sweet xylitol
Artificial powdered sweeteners such as sucralose (like Splenda) or aspartame (like Canderel) can be used but they may raise blood glucose levels slightly and can leave a bitter aftertaste.
For the best outcomes with this recipe it is best to use the ingredients recommended and in the quantities stated.


Calories: 92kcal | Carbohydrates: 7g | Protein: 2g | Fat: 7g | of which saturates: 2g | Fibre: 3g | of which sugars: 1g