Is there any Sugar in kale?

Kale is often touted as a super healthy green vegetable that is low in calories and high in nutrients. However, some people may be concerned about the sugar content in kale. So does kale actually contain sugar? Let’s take a closer look.

The Basics of Kale

Kale is a leafy green vegetable that belongs to the Brassica family, which also includes broccoli, cauliflower, and Brussels sprouts. Some common varieties of kale include curly kale, dinosaur kale, and red Russian kale. Kale is chock full of vitamins, minerals, and antioxidants. Some of the standout nutrients in kale include:

  • Vitamin K
  • Vitamin A
  • Vitamin C
  • Calcium
  • Potassium
  • Magnesium
  • Iron
  • Fiber

Kale is definitely recognized as one of the healthiest foods you can eat. But how does its sugar content stack up?

Does Kale Have Natural Sugars?

All vegetables contain some naturally occurring sugars. The sugars found in whole, unprocessed vegetables like kale are from complex carbohydrates. Kale contains carbs in the form of fiber and sugars.

One cup of raw kale (about 67 grams) contains:

  • 7 grams of carbohydrates
  • 1 gram of naturally occurring sugar
  • 2 grams of dietary fiber

So in a typical serving size of kale, it does contain 1 gram of sugar. Where does this sugar come from?

The naturally occurring sugar in kale is called glucose. Glucose is a simple sugar and the most common carbohydrate found in plant foods. During photosynthesis, plants like kale produce glucose and store it as starch and fiber in the leaves. The small amount of sugar in kale is glucose that helps provide energy for the plant’s growth and development.

How Does Kale’s Sugar Content Compare to Other Foods?

To put kale’s sugar content into context, let’s compare it to some other common foods.

Food Serving Size Total Carbs Sugars
Kale 1 cup 7 grams 1 gram
Apple 1 medium 25 grams 19 grams
Banana 1 medium 27 grams 14 grams
Broccoli 1 cup 6 grams 1 gram
Carrot 1 medium 7 grams 3 grams
Orange 1 medium 15 grams 12 grams
Yogurt 1 cup 12 grams 12 grams

As you can see, kale is very low in sugar compared to sweet fruits like apples, bananas, and oranges. It contains minimal sugar compared to even other vegetables like carrots. The only comparable food is broccoli, which has an almost identical sugar content.

Does Cooking Impact Kale’s Sugar Content?

When it comes to the sugar in kale, it doesn’t make much difference whether you eat it raw or cooked. Cooking kale by steaming, sautéing, roasting, etc. does not significantly increase its sugar content. Here is the sugar content of cooked kale compared to raw:

Type Serving Total Carbs Sugars
Raw kale 1 cup 7 grams 1 gram
Steamed kale 1 cup 8 grams 1 gram
Sautéed kale 1 cup 6 grams 1 gram

As you can see, the total carbs and sugars remain very consistent whether kale is served raw or cooked. So cooking does not significantly increase the sugar levels.

What About Added Sugars in Kale?

While kale itself does not contain high amounts of sugar, some pre-packaged kale products do contain added sugars. For example:

  • Pre-made kale smoothies or juices – May have fruit juices, honey, or other sweeteners added.
  • Salad mixes with dressing – Dressings and croutons add extra carbs and sugar.
  • Chips or snacks made from kale – Often include extra ingredients like sugar, salt, and oil.

To avoid added sugars in kale, it’s best to stick to plain, unprocessed kale you prepare yourself. Steer clear of kale products with dressings, dips, juices, smoothies, or other ingredients.

Does Kale Have Added Sugars?

When it comes to added sugars, plain raw or cooked kale does not contain any. However, packaged or prepared kale foods may contain added sweeteners such as:

  • Fruit juice – Apple, orange, pineapple juice are often added to kale smoothies and juices.
  • Honey – May be mixed into dressings for kale salads or chips.
  • Cane sugar – Sometimes sprinkled onto kale chips or blended into dips.
  • Brown rice syrup – Used as a sweetener in some packaged kale snacks.
  • Maple syrup – Often found in sweet kale smoothies or salad dressings.

Always check the ingredient label for added sugars if choosing pre-made kale products. Stick to plain fresh or frozen kale that you prepare at home to avoid added sweeteners.

Does Kale Impact Blood Sugar?

For people with diabetes or prediabetes, a common question is “Does kale affect my blood sugar levels?” The answer is that kale has a very low glycemic index and glycemic load.

The glycemic index (GI) measures how much a food raises blood glucose. Kale scores a 15 on the GI, compared to 65-70 for white bread. A GI under 55 is considered low.

Glycemic load (GL) factors in the carb content of a serving. Kale has an extremely low GL of just 1, versus white bread which has a GL of 10-15 per slice.

The minimal carb and sugar content of kale means it has an insignificant effect on blood sugar. It’s considered one of the best low glycemic vegetables you can eat.

Does Blending or Juicing Impact Kale’s Sugars?

Juicing and blending kale into smoothies can raise the glycemic index compared to eating it whole. This is because the juicing process removes the fiber, leaving only the sugars and carbs behind in the juice. The fiber in whole vegetables helps slow their digestion and absorption.

For example, a 1 cup serving of kale juice would have approximately:

  • 7 grams carbs
  • 1 gram sugar
  • 0 grams fiber

Compare this to a whole cup of kale with 7 grams carbs, 1 gram sugar, and 2 grams fiber. While juicing doesn’t add any new sugars to kale, it can raise the GI by removing the protective fiber.

Blending kale leaves the fiber intact, so green smoothies would have a minimal glycemic impact like whole kale. But adding fruit juices and sweeteners to smoothies will raise their carb and sugar content.

Does Cooking Kale Reduce Its Nutrients?

Light cooking can make some of kale’s nutrients more absorbable by softening the tough cell walls. For example, steaming kale for just 1-2 minutes can increase the bioavailability of carotenoid antioxidants. However, excessive heat can damage nutrients like vitamin C and enzymes. Here’s a look at how different cooking methods impact kale:

  • Steaming: Quick steaming retains most nutrients but softens kale leaves. Steaming for under 5 minutes is recommended.
  • Sautéing: Cooking briefly in olive oil softens leaves while preserving nutrients.
  • Roasting: Roasting at high heat for too long can degrade some heat-sensitive vitamins.
  • Boiling: By leaching nutrients into the water, boiling causes more nutrient loss than steaming.
  • Microwaving: Microwaves can lead to greater losses of vitamin C and antioxidants.

For maximum nutrition, eat a mix of raw kale and kale lightly steamed or sautéed for just a couple minutes. Avoid boiling or microwaving for long periods.

Health Benefits of Kale

Given its stellar nutrition profile, kale provides an abundance of health benefits. Here are some of the top ways kale can boost your health:

  • Powerful antioxidants: Kale contains antioxidants like quercetin, kaempferol and vitamin C that help combat oxidative stress and inflammation in the body.
  • Anti-cancer properties: The glucosinolates in kale may lower the risk of certain cancers like lung, prostate, breast and colon cancer.
  • Heart health: Kale contains heart-healthy nutrients like omega-3s, magnesium, fiber, vitamin K, and potassium.
  • Bone health: The calcium, magnesium, phosphorus, and vitamin K in kale promote healthy, strong bones.
  • Immune function: The antioxidants, vitamin C, and other compounds in kale strengthen the immune system.
  • Detoxification: Kale supports the body’s natural detox processes thanks to its antioxidant content and bile-stimulating effects.
  • Digestion: The fiber in kale promotes regularity, gut health, and digestive comfort.
  • Vision health: Lutein and zeaxanthin act as antioxidants that protect the eyes from UV damage.

Risks or Precautions with Eating Kale

For most people, kale is an incredibly healthy and safe food to include in their diet. However, there are a few precautions to keep in mind:

  • Pesticide residue – Buy organic. Kale is often heavily sprayed with pesticides.
  • Thyroid function – Kale contains goitrogens, so those with thyroid issues may need to moderate intake.
  • Kidney stones – The oxalates in kale may be problematic for those prone to kidney stones.
  • Blood clotting – Very high vitamin K intake could interfere with blood thinners.
  • Digestive issues – Some find raw kale tough to digest. Cook lightly if needed.

Pregnant women, older adults, and anyone on medication should check with a doctor before significantly increasing kale consumption.


Kale is an exceptionally healthy vegetable that contains a wide array of vitamins, minerals, antioxidants, and other beneficial plant compounds. While kale does contain trace amounts of naturally occurring sugar in the form of glucose, its total sugar content is extremely low.

Enjoying kale raw, steamed, roasted, or sautéed will provide minimal effects on blood sugar levels. Just be aware of potential added sugars in packaged kale products like smoothies. Given its stellar nutrient profile and low calorie and carb content, kale is a wonderful addition to a healthy, balanced diet.

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