Kale vs Spinach: Which is Better? A Complete Comparison

Kale and spinach are two superfoods often used together or in place of the other. Many people wonder if there’s much of a difference between the two. Let’s examine, what is the difference between kale and spinach?

Kale is a leaf cabbage belonging to a group of cabbage cultivars while spinach is a leafy green belonging to the Amaranthaceae family. Kale’s leaves are harder and coarser than spinach. Spinach is a dark green while kale’s color can range from light green to a violet-green. Kale tastes more bitter and spinach provides more nutrients.

This article will examine both foods including a side-by-side nutrient comparison. In addition, I’ll take a close look at their tastes, textures, prices, glycemic index, health benefits and if one can substitute for the other.

As a Certified Health Coach many clients have asked me about kale and spinach. In addition to coaching clients about them, I’ve purchased, researched and consumed both prior to, during and after writing this article.

The Difference Between Kale and Spinach

Both are nutritious, leafy greens often used interchangeably in recipes, but there are some key differences between the two. Kale is a member of the cabbage food category, and its leaves are hard and have a slightly bitter taste. 

In contrast, spinach is a member of the Amaranthaceae family, and its leaves are soft and have a milder taste but can be bitter also. 

Both are highly nutritious and low-calorie foods that provide a variety of vitamins and minerals with some fiber and protein 1. However, they have different concentrations of nutrients 2. 

Kale and spinach in bowls
Kale on the left spinach on the right

Kale vs Spinach Nutrition

The following table compares the nutrients per 100 grams.

Spinach, raw (100 g) Kale, raw (100 g)
Calories 23 35
Protein 2.86 g 2.92 g
Carbohydrates 3.63 g 4.42 g
Fiber 2.2 g 4.1 g
Fat 0.39 g 1.49 g
Sugar 0.42 g 0.80 g
Vitamin A 9,380 IU 4,480 IU
Beta-carotene 5,630 mcg 2,870 mcg
Vitamin C 28.1 mg 93.4 mg
Vitamin K 483 mcg 390 mcg
Vitamin D 0 IU 0 IU
Vitamin B6 0.19 mg 0.15 mg
Vitamin B9 (Folate) 194 mcg 62 mcg
Vitamin B1 (Thiamin) 0.08 mg 0.11 mg
Vitamin B2 (Riboflavin) 0.19 mg 0.35 mg
Vitamin B3 (Niacin) 0.72 mg 1.18 mg
Vitamin B5 (Pantothenic Acid) 0.07 mg 0.37 mg
Magnesium 79 mg  33 mg
Phosphorous 49 mg  55 mg
Potassium 558 mg 348 mg
Iron 2.71 mg 1.60 mg
Copper 0.13 mg 0.05 mg
Calcium 99 mg 254 mg
Zinc 0.53 mg 0.39 mg

Nutrient Resources 3 4

Looking at the nutrient table above it’s difficult to determine if one is better than the other, the nutrients are pretty similar. Let’s examine which is healthier.

Kale and spinach are nutrient dense and provide a similar number of nutrients. For this reason, they are equally healthy and both should be part of a well-rounded, healthy diet.

There are some nutrients kale is higher in. It provides a higher percentage of protein, fiber, vitamin C, thiamin, niacin, riboflavin, B5, phosphorous and calcium.

Spinach provides a higher percentage of vitamin A, beta carotene, vitamin K, B6, folate, magnesium, potassium, iron, copper and zinc.

Check down further in the article to find out about the health benefits of these two superfoods and nutrients. Choosing one over the other may depend on your particular goals and lifestyle category. Let’s examine some of those goals next.

I use spinach more but I purchase and consume both almost daily. I use baby spinach for salads and smoothies. I often use the frozen varieties which I add directly into a smoothie prior to mixing all the ingredients.

The following video compares both vegetables.

Which to Choose

Low-carb or Keto Diet

The number one thing to look at first while on a low-carb diet is the carbohydrates. Therefore, let’s examine the carbohydrates provided.

Kale has 0.79 more carbohydrates than spinach per 100 grams. While this doesn’t sound like much of a difference, it has 21% more carbohydrates. On a keto diet a small difference may mean a lot. Therefore, spinach is better for low-carb diets.

Weight Loss

If you’re counting calories to lose extra fat around the middle, you may be wondering which one benefits weight loss.

Spinach contains 12 fewer calories than kale per 100 grams. While this doesn’t sound like much of a difference, it results in a 50% difference in calories. Therefore, spinach is better for weight loss if you’re counting calories.

Gluten Free

If you’re consuming a gluten free diet or have celiac disease, this can make or break your choice between the two. Which is gluten free?

Kale and spinach are gluten free. Therefore, if you have celiac disease, both of them are good options.

Bodybuilding

If you’re trying to gain lean muscle mass, your carbohydrate and protein intake are important. The extra protein helps to repair and build new muscle after a workout. The extra carbohydrates help to fuel energy and increase exercise performance when lifting weights.

Let’s examine which is better for bodybuilding.

Kale provides 0.6 more grams of protein per 100 grams, approximately 2% more than spinach. Kale provides 0.79 more carbohydrates per 100 grams, 21% more. It also provides a little more calories which can help when bulking up.

Therefore, kale is better for bodybuilding.

spinach and kale nutrient comparison

Taste and Texture

Sometimes the difference in nutrients or calories may not matter, and the decision to choose one of the foods comes down to how good it tastes. Therefore, let’s examine the difference in the taste and texture.

Kale has a slightly bitter taste compared to the milder spinach. Spinach may taste bitter to some people but not as much as kale. Kale leaves are harder and chewier than the softer spinach leaf. When kale is cooked, it retains more of its tougher texture than spinach which becomes softer.

I wanted to conduct original research and find out what real people like you thought about the taste of kale and spinach. Therefore, I polled my clients, readers and people belonging to food groups and asked, what tastes better?

  • 59% said they preferred the taste of spinach.
  • 34% said they preferred the taste of kale.
  • 7% said they had no preference.

Home Taste Test

To conduct more research I setup and participated in a taste test at home. Two out of three of us chose spinach for it better and less bitter flavor.

Substituting

For many different reasons, you may want to use one of the two foods in a recipe calling for the other food. For these reasons, you’ll need to know if they can substitute for each other.

Kale and spinach can substitute for each other although the texture will be different due to the coarser kale. When substituting in salads use a one to one ratio. When cooking use more spinach due to how it breaks down while cooked.

Substitute both in the following dishes:

  • Salads
  • Smoothies
  • Curries
  • Casseroles
  • Soups
  • Sandwiches
  • Tacos

Additional Tips:

  • When using kale in salads, massaging the leaves can make them more tender and less hard. In addition, always destem it.
  • Kale can be cut up finer so it cooks thoroughly and to soften up quicker if desired.
  • To achieve a softer texture from kale, cook it longer.

You may want to use both of them together in the same salad or dish. Some of the food manufacturers have made this easy for you by selling them together in the same container or bag in the produce section.

The following video explains to you an easy way to make a kale salad.

Prices

How much food cost is important to most people. Lately, it seems the price of grocery items keeps getting higher. Therefore, let’s take a close look the prices, kale vs spinach.

Fresh kale costs more money per ounce than spinach. The cost for fresh kale averages $0.24 per ounce and spinach averages $0.16 per ounce. 

To conduct some original research, I visited some local supermarkets and checked the prices of both. Here are my findings.

First I visited a Walmart Supercenter:

  • Marketside bagged fresh spinach
    • 10 ounce bag for $1.98. Equals $0.20 per ounce
  • Marketside fresh kale
    • 16 ounce container for $4.84. Equals $0.30 per ounce

I then checked my local Shoprite supermarket:

  • Bowl and basket chopped spinach
    • 10 ounce bag for $1.29. Equals $0.13 per ounce
  • Bowl and basket kale
    • 16 ounce bag for $2.99. Equals $0.18 per ounce
checking kale and spinach prices at my local supermarket
Checking kale and spinach prices at my local supermarket

Glycemic Index for Kale and Spinach

Blood sugar spikes may lead to health complications over time 5. For this reason, avoiding blood sugar spikes as often as possible is an important part of a healthy diet.

The glycemic index measures how fast food raises blood sugar levels 6Foods on the GI scale are categorized as:

  • Low-GI foods: 55 or under
  • Medium-GI foods: 56-69
  • High-GI foods: 70 or over

How blood sugars levels are affected:

  • Foods with a glycemic index 70 or more cause a quicker spike in blood sugar levels.
  • Foods with a glycemic index 56 to 69 cause a moderate spike in blood sugar levels.
  • Foods with a glycemic index 55 or less cause a slow spike in blood sugar levels.

Kale and spinach are both low glycemic foods and shouldn’t cause any spikes in blood sugar. Besides the two, all leafy greens have a low glycemic index, almost unmeasurable in some varieties. This increases their benefits.

Kevin Garce checking spinach and kale in his local supermarket.
Checking spinach and kale in the produce section of my local supermarket

Health Benefits

Dietary Fiber

  • Kale provides 86% more fiber per 100 grams.

Soluble fiber is helpful for many reasons 7. What makes fiber soluble is it dissolves in water. 

Soluble fiber is known for the following:

  • Help overall digestion.
  • Helps to have a more regular stool and avoid constipation.
  • Manage the blood glucose levels which helps decrease the risk of diabetes.
  • Aids greatly in weight management because it allows you to feel full faster and eat less. 

Find out if collard greens have more nutrients in my article.

cutting and desteming kale on a cutting board
Cutting and desteming kale

Protein

  • Kale provides 2% more protein per 100 grams.

Protein is helpful for many reasons 8. Protein is known for the following:

  • Helps to build, repair and maintain muscle.
  • Aids in weight management because it allows you to feel full eat less later. 
  • Can help increase metabolism.

Low levels of protein may result in the following:

  • Anemia
  • Impaired immunity
  • Physical weakness
  • Edema
  • Vascular dysfunction

Minerals

Spinach provides a higher percentage of five of the seven minerals listed in the nutrient table above. The difference in minerals between the two is significant. Therefore, let’s take a close look at the minerals and discuss how they may benefit health.

Magnesium

Magnesium helps the body control the following:

  • Blood sugar
  • Systolic and diastolic blood pressure
  • Insomnia
  • Nerve function
  • Muscle function

In the heart and muscles, magnesium competes with calcium to help the muscles relax after contracting. When the body is low in magnesium, calcium can over stimulate the heart muscle’s cells causing a rapid or irregular heartbeat 9.

One reason many people supplement with magnesium in the evening is because it helps calm the whole body including blood vessels.

Magnesium helps keep blood pressure levels stable and balanced. Recent scientific research examined previous studies and concluded magnesium supplementation decreased systolic and diastolic blood pressure 10.

Find out if Swiss chard has more nutrients in my article, Spinach vs Swiss Chard: Which is Better? Complete Comparison.

Potassium

Some medical experts recommend the potassium to sodium ratio of 4:1. Consuming too much sodium or not enough potassium throws off the delicate balance the kidneys need to remove the excess water 11.

Potassium helps the body reduce excess fluid and blood pressure 12.

According to Harvard Health, a number of studies have shown a connection between low potassium levels and high blood pressure 13. The more potassium, the more sodium your body will lose.

Iron

Iron is a necessary part of any healthy diet 14. Iron may help with the following:

  • Is essential the creation of red blood cells.
  • Vital for growth and development.
  • Help some hormones remain balanced.
  • Help the immune system.

Phosphorus

Phosphorus has been shown in scientific studies to help with the following:

  • Promote healthy nerve conduction.
  • Help the body manage and store energy.
  • Help the kidneys remove waste.
  • Muscle contraction and recovery.
  • Promote bone and teeth health.

Calcium

Calcium helps the following:

  • Help the muscles to function properly.
  • Helps nerve function.
  • Maintain and build strong bones.

In addition, calcium is important for the heart and blood pressure. Harvard Health reports calcium helps maintain blood pressure by helping in the controlling of the relaxing and tightening of blood vessels 15.

Find out the differences between these two spinach varieties in my comparison article.

kale side dish
Kale side dish

Vitamin

Vitamin C

Vitamin C acts as an antioxidant and helps with the following:

  • Prevent cell damage.
  • Increases iron absorption.
  • Help maintain health gums.
  • Collagen production.
  • May help boost the immune system.
  • Help heal wounds.

Vitamin A & Beta Carotene

  • Spinach provides 109% more vitamin A and 96% more beta carotene per 100 grams.

Beta-carotene is a compound present in both. The body converts beta-carotene into vitamin A. Vitamin A is a powerful antioxidant that can help reduce cellular damage by controlling the negative effects of free radicals 16.

An increased number of vitamin A has been shown to fight and prevent cardiovascular disease, which is the leading cause of death in the United States 17.

According to scientific studies, vitamin A helps the eyes when it comes to dim light vision and dry eyes 18.

Find out if which type has more nutrients in my article, Raw Spinach vs Cooked Spinach: Which is Better? A Comparison.

B Vitamins

The B vitamins provided include the following:

  1. B1 (thiamin)
  2. B2 (riboflavin)
  3. B3 (niacin)
  4. B5
  5. B6
  6. B9 (folate)

B vitamins help support the following:

  • Digestion.
  • Nerve function.
  • Brain function.
  • Red blood cells.
  • Energy levels.
  • Cardiovascular disease.

Below is another video which compares kale and spinach.

Find out if romaine is healthier in my article here.

If you have any questions about this article don’t hesitate to email us. You can find an email on our contact page.

Read More Spinach Food vs Food Articles

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Frozen Spinach vs Fresh: Which is Better? A Comparison

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Organic Spinach vs. Regular Spinach: What’s The Difference?

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Article Resources: Foods For Anti-Aging follows strict guidelines to ensure our content is the highest journalistic standard. It's our mission to provide the reader with accurate, honest and unbiased guidance. Our content relies on medical associations, research institutions, government agencies and study resources. Learn more by reading our editorial policy.
  1. Wikipedia: Kale[]
  2. Wikipedia: Spinach[]
  3. USDA: Spinach, raw[]
  4. USDA: Kale, raw[]
  5. National Institute of Diabetes and Digestive and Kidney Diseases: Know Your Blood Sugar Numbers: Use Them to Manage Your Diabetes[]
  6. Harvard Health Publishing: Glycemic index for 60+ foods[]
  7. National Center for Biotechnology Information: Mechanisms linking dietary fiber, gut microbiota and colon cancer prevention[]
  8. National Center for Biotechnology Information: Dietary protein intake and human health[]
  9. National Institutes of Health: Magnesium[]
  10. National Center for Biotechnology Information: Effect of magnesium supplementation on blood pressure: a meta-analysis[]
  11. National Center for Biotechnology Information: The Effect of the Sodium to Potassium Ratio on Hypertension Prevalence: A Propensity Score Matching Approach[]
  12. American Heart Association: How Potassium Can Help Control High Blood Pressure[]
  13. Harvard Health: Potassium lowers blood pressure[]
  14. National Institutes of Health: Iron[]
  15. Harvard Health: Key minerals to help control blood pressure[]
  16. National Center for Biotechnology Information: Free radicals, antioxidants and functional foods: Impact on human health[]
  17. National Center for Biotechnology Information: Antioxidant potentials of vitamin A and carotenoids and their relevance to heart disease[]
  18. National Center for Biotechnology Information: Nutrients for the aging eye[]

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