Blackberries are a delicious, nutritious fruit that can be a great addition to a low-carb diet. With only 10-15 grams of net carbs per cup, blackberries contain fewer carbs than many other fruits. However, the carb count can vary depending on the size and type of blackberry. In this article, we’ll take a detailed look at the carb content of blackberries and whether they can be considered low-carb.
Are Blackberries Low in Carbs?
Compared to other fruits, blackberries are relatively low in carbs. Here is how they stack up (in grams of net carbs per 100g of raw fruit):
| Banana | 23g |
| Apple | 13g |
| Mango | 17g |
| Grapes | 18g |
| Strawberries | 8g |
| Raspberries | 12g |
| Blueberries | 14g |
| Blackberries | 10g |
As you can see, blackberries contain fewer carbs per serving than popular fruits like bananas, apples, mangoes, and grapes. They have a similar carb count to raspberries and blueberries.
So while they aren’t extremely low in carbs like avocados or coconut, blackberries can certainly be considered low-carb compared to other fruits.
Net Carbs in Blackberries
To get a true picture of the carb content, we need to look at the net carbs in blackberries.
Net carbs are calculated by subtracting the grams of dietary fiber from the total carb count. Fiber does not raise blood sugar or require insulin like other carbs.
Here are the macronutrients in one cup (144g) of raw blackberries (1):
| Total Carbs | 15g |
| Fiber | 8g |
| Net Carbs | 7g |
With 8g of fiber per cup, the net carbs come out to only 7g for a standard serving size. This carb count can fit well within a low-carb eating plan.
The takeaway: while blackberries contain 15g total carbs, the high fiber content reduces the net carbs to just 7g per cup.
Carb Differences Between Blackberry Types
There are many different species and hybrids of blackberries:
- Thornless blackberries
- Semi-erect blackberries
- Trailing blackberries
- Erect blackberries
- Marionberry – hybrid species developed in Oregon
Additionally, commercial varieties tend to be larger and sweeter than wild blackberries.
This can result in carb differences between types. Larger, juicier blackberry varieties tend to have more carbs.
For example, a cup of raw Marion blackberries has about 13g net carbs, while the same amount of wild blackberries has around 9g net carbs (1, 2).
So if you are carefully tracking carbs, be aware the nutrition facts can vary across blackberry species and cultivars. The typical range is 7-13g net carbs per cup.
Blackberry Serving Size Carbs
As with all fruits and vegetables, the carbohydrate content will depend on your serving size.
Here are the net carbs in different serving sizes of raw blackberries (1):
| 1/2 cup blackberries | 4g net carbs |
| 1 cup blackberries | 7g net carbs |
| 10 medium blackberries | 3g net carbs |
| 1 extra large blackberry | 2g net carbs |
A smaller serving of 10 medium blackberries provides just 3g net carbs, which is easy to incorporate into a low-carb meal plan. But a larger 2 cup portion could contain up to 30g total carbs and 22g net carbs.
The takeaway: stick with 1 cup or less per serving if you want to reap the benefits of blackberries without going over your daily carb limit.
Do Blackberries Spike Blood Sugar?
For people with diabetes or prediabetes, it’s important to consider a fruit’s glycemic index (GI). This measures how quickly a food causes spikes and crashes in blood sugar levels.
Blackberries have a remarkably low glycemic index of 25, compared to other popular fruits (3):
| Bananas | GI 55 |
| Grapes | GI 53 |
| Apples | GI 38 |
| Strawberries | GI 40 |
| Blackberries | GI 25 |
This means blackberries have minimal impact on blood sugar. The polyphenols and fiber in blackberries help slow the digestion and absorption of carbohydrates (4).
Additionally, a study in healthy and diabetic rats found blackberry extract actually helps regulate blood sugar response and improve insulin levels after carb-containing meals (5).
The antioxidant compounds in berries also appear to reduce inflammation and oxidative stress associated with hyperglycemia (high blood sugar) (6).
Overall, the research indicates blackberries are an excellent fruit choice for people with diabetes. They help support healthy blood sugar regulation.
Blackberries on a Keto Diet
The very low-carb ketogenic diet limits daily net carbs to 20-50g per day.
This allows few servings of carb-containing foods. However, berries are one of the best fruit options on keto, in moderation.
Here are some tips for fitting blackberries into a keto eating plan:
- Stick to 1/2 – 1 cup portion sizes
- Pair with low-carb foods like plain Greek yogurt
- Mix into a keto smoothie with collagen, almond milk, and spinach
- Use as a topping for keto pancakes or waffles
- Mix into chia pudding made with coconut milk
While blackberries cannot be a staple in a keto diet, enjoying them occasionally can add nutrients and variety.
Carbs in Blackberries vs. Blueberries
Blackberries and blueberries are both nutrient-dense berries low in carbs.
But blueberries contain slightly more carbs and sugars:
| Blackberries | Blueberries | |
|---|---|---|
| Net carbs per cup | 7g | 12g |
| Sugars per cup | 4g | 10g |
The natural pigments that give blueberries their color also contribute more carbohydrate than blackberries (7).
Additionally, some varieties of blueberries can be much larger and sweeter than blackberries. So the carb difference may be even greater depending on the specific type.
Both berries are low-glycemic and full of antioxidants. But blackberries contain fewer carbs if you are strictly monitoring your intake.
Do Blackberries Have Sugar Alcohol?
Some low-carb packaged foods use sugar alcohols as sweeteners to provide fewer net carbs.
However, whole blackberries do not naturally contain sugar alcohols like erythritol, xylitol, or maltitol.
The total sugars in blackberries include (1):
- Glucose – 2.4g
- Fructose – 1.6g
- Sucrose – 0.9g
So the 4g of sugar in a serving of blackberries comes from glucose, fructose, and a small amount of sucrose.
This natural fruit sugar has a lower glycemic impact than added sugars or syrups. But there are no sugar alcohols present unless blackberries are processed and sweetened.
Should You Eat Blackberries on a Low-Carb Diet?
With only 7g net carbs per cup, blackberries can certainly fit into a low-carb eating plan.
Here are some of the benefits of eating blackberries on a low-carb diet:
- High in fiber – the 8g of fiber offsets some of the total carb content
- Low glycemic impact – minimal effect on blood sugar
- Antioxidants – blackberries provide polyphenols and anthocyanins that reduce inflammation
- Gut health – the fiber promotes a healthy microbiome
- Vitamins & minerals – excellent source of Vitamin C, manganese, and Vitamin K
Blackberries can be a smart addition to a low-carb diet when consumed in moderation. 1/2 – 1 cup serving a few times per week provides benefits without going over carb limits.
Tips for Low-Carb Blackberry Recipes
Here are some recipes and serving ideas for enjoying blackberries on a low-carb diet:
Chia Blackberry Parfait – combine blackberries with chia seeds, coconut milk, cinnamon, and stevia. Layer in a mason jar for an easy breakfast.
Blackberry Smoothie – blend blackberries, almond milk, collagen peptides, spinach, and ice.
Blackberry Cheese Danish – use fathead pizza dough to make a low-carb danish with blackberry topping and cream cheese filling.
Grilled Chicken Salad – top a salad of spinach, grilled chicken, avocado, red onion, walnuts, and feta cheese with fresh blackberries.
Blackberry Sorbet – puree frozen blackberries with a bit of stevia and coconut cream for a low-carb frozen dessert.
Blackberry Muffins – make keto-friendly muffins with almond flour, butter, eggs, and blackberries.
Blackberry Frozen Yogurt Bark – blend Greek yogurt, blackberries, and lemon juice, then freeze into popsicle molds for a tasty low-carb snack.
Potential Downsides of Blackberries
Blackberries are loaded with beneficial nutrients and antioxidants. There are a few things to keep in mind, however:
- Carb counts can add up quickly in large servings
- They contain moderate sugar content relative to other fruits
- Some people may be sensitive to the small amounts of natural salicylates
- Blackberries need to be limited on stricter ketogenic diets
- Raw blackberries have a short shelf life and can mold quickly
As with any plant food, moderation is key. Pay attention to serving sizes and enjoy blackberries as part of an overall healthy low-carb diet.
The Bottom Line
Blackberries provide a number of benefits and can be enjoyed in moderation on a low-carb diet.
With only 7g net carbs per cup, blackberries are relatively low in carbs for a fruit. But the nutrition facts can vary across different blackberry cultivars and serving sizes.
The polyphenols and fiber in blackberries give them a low glycemic index, which means they have a minimal impact on blood sugar levels.
Enjoy blackberries in smoothies, salads, chia puddings, frozen treats, and other low-carb recipes. But limit your portions to 1 cup or less per serving.
At the end of the day, blackberries are a smart low-carb fruit choice with plenty of nutrition upside.
