Green Smoothie (Peanut Butter Banana)

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My favorite green smoothie is packed with protein, fiber, and healthy fats to keep you full, plus loaded with nutrients and antioxidants. The combo of peanut butter and banana makes it taste more like a milkshake than a healthy smoothie!

Green smoothie topped with chia seeds

This green smoothie provides probiotics and prebiotics to for gut health, antioxidants to fight inflammation, and the perfect balance of protein, fiber, and healthy fats to support weight and energy levels! Each ingredient used is nutrient-dense, creating a delicious and satisfying smoothie when blended together.

To learn more about the benefits of gut health, check out my article Superfoods for Gut Health.

What You’ll Need

All you’ll need is a blender and a few simple ingredients to make this smoothie. 


Ingredients and Health Benefits 


Kefir is a fermented dairy beverage similar to yogurt, but with a thinner consistency. Kefir provides probiotics to support gut health, adding to the number and diversity of beneficial bacteria found in the gut.

While both yogurt and kefir are great sources of probiotics, kefir offers 2-3x more probiotics than yogurt. 

To put this into perspective, one serving of kefir provides 12 strains (aka, different types) of live and active probiotic bacteria and 25-30 billion CFU (colony forming units). In comparison, one serving of yogurt provides 2-5 strains of probiotics and 6 billion CFU.

This simply means that kefir offers a higher number and diversity of beneficial bacteria that support a healthy gut. 

In addition to probiotics, kefir is also a good source of calcium, magnesium, tryptophan, and B-vitamins.

Due to the magnesium and tryptophan found in kefir, it naturally promotes rest and relaxation in the body, and helps to increase production of the neurotransmitter serotonin which eases anxiety and boosts mood. 

This recipe calls for 1 cup of plain kefir, which has 0 grams of added sugar. If using flavored kefir, choose a variety with less than 8 grams of added sugars. 


Bananas are well-known for their potassium content, which helps to regulate blood pressure levels and aid in muscle contraction, but they have many other health benefits as well. 

Bananas are a great source of prebiotic fiber, providing around 3 grams of fiber per banana. Prebiotics act as the “fuel” for our healthy gut bacteria, allowing them to grow in number and diversity. Prebiotic fiber is essential for a healthy gut. 

Like kefir, bananas are also high in tryptophan and magnesium which help to naturally boost serotonin levels. In addition, bananas contain vitamin B6 which is also required for the production of serotonin. 

This means that bananas provide many of the nutrients necessary for producing serotonin, helping to to promote a feeling of calm and relaxation.

You’ll need one banana for this recipe. I prefer to use frozen bananas for a thicker consistency, but you can also use a fresh banana and increase the amount of ice used. 

Pro tip: for an extra thick and creamy smoothie, use frozen bananas instead of fresh! Simply remove the peel from your bananas once they’re beginning to become over-ripe, place into a freezer bag, and freeze. I always have a bag of frozen bananas in my freezer for smoothies! 

Avocado (Optional)

Avocados are a nutrient-dense food, packing a wide range of nutrients per calorie. According to the USDA, ½ of an avocado provides the following nutrient profile: 

  • 160 calories
  • 14.7 grams fat (primarily monounsaturated fat)
  • 8.5 grams carbohydrate
  • 6.7 grams of fiber 
  • 2 grams of protein
  • 1.4 grams vitamin B5 (28% DV)
  • 81 mcg folate (20% DV)
  • 2.1 mg vitamin E (14% DV)
  • 485 mg potassium (10% DV)

The monounsaturated fats in avocados lower inflammation and LDL-cholesterol levels when replacing saturated and trans fats in the diet (1). 

Because monounsaturated fats also lower inflammation in the brain, avocados are considered to be a “brain food,” as they play a role in slowing cognitive decline and protecting brain function (2).

Avocados also have an impressive antioxidant profile including vitamins A, C, and E, lutein, zeaxanthin, and other phytochemicals. Together, these antioxidants and phytochemicals help to fight inflammation and protect our cells from oxidative stress, reducing the risk of disease (3). 

I like to use ½ of an avocado if I have a ripe one on hand, because they’re full of fiber and healthy fats, and make the smoothie extra creamy and satisfying. 


Spinach is one of the most nutrient-dense foods you can eat. 

One serving of spinach (2 cups fresh) provides the following nutrients for only 20 calories:

  • 2 grams protein
  • 2 grams fiber
  • 340% vitamin K
  • 45% vitamin A
  • 40% folate  
  • 35% manganese
  • 25% vitamin C
  • 15% iron 
  • 10% potassium
  • 6% calcium 

Spinach is also rich in antioxidants that protect our cells from harmful free radicals and oxidative stress, helping to reduce inflammation and slow the aging process. 

In particular, spinach is one of the best sources of lutein, an antioxidant that is known to protect the brain from cognitive decline and is shown to actually improve memory and cognitive function (4).  

While you’ll be able to see that there’s spinach in this smoothie due to the green color, there’s no noticeable taste or texture because it blends up so well, so you’ll receive all the benefits that spinach has to offer without noticing it!

Adding spinach to smoothies is a great way to get kids to eat spinach too, because they won’t even know it’s in there (just add berries to hide the green color). 

Ground Flaxseed

Flaxseeds are full of fiber, protein, healthy fats, and antioxidants that support a healthy diet. 

One tablespoon of ground flaxseed provides 3 grams of prebiotic fiber which strengthens gut health, aids in digestion, reduces blood sugar and cholesterol levels, and supports weight management by keeping you feeling full longer. 

It also provides 2 grams of plant-based protein per tablespoon, making it an easy way to boost the protein content of your smoothies. 

In addition, flaxseed is one of the best sources of plant-based omega-3 fats, which have powerful anti-inflammatory properties.

Flaxseeds are rich in antioxidants that fight inflammation and reduce the risk of disease, including vitamin E, lignans, and p-Coumaric acid.

I prefer ground flaxseed because it easily mixes into yogurt, oatmeal, smoothies, baked goods, and other foods without a noticeable texture. You’ll use one tablespoon of ground flaxseed in this smoothie. 

Chia Seeds

Like flaxseeds, chia seeds are also a great source of plant-based fiber, protein, omega-3 fats, and antioxidants. 

Chia seeds do have slightly higher amounts of fiber, protein, and omega 3 fats compared to flaxseed, providing 4 grams of fiber and 2.5 grams protein per tablespoon (5). 

However, flaxseeds offer a higher antioxidant profile than chia seeds, which helps protect us from oxidative stress and disease. 

Since both chia and flaxseed have their own unique health benefits, I recommend using both in your diet. I like to use ground flaxseed in yogurt, oatmeal, and baked goods, while chia seeds have a more noticeable texture so I prefer to use these in smoothies. 

To reap the benefits of both, we’ll be using 1 Tbsp. of ground flaxseed and 1 Tbsp. of chia seeds to this smoothie to boost the fiber, protein, omega-3, and antioxidant content.

Peanut Butter or Peanut Butter Powder

Nut butters are a great way to boost the content of fiber, protein, and healthy fats in smoothies. While any nut butter of your choice could be used, I like to use peanut butter powder because it still gives that irresistible peanut butter taste with 3x fewer calories and fat than normal peanut butter. 

One serving of peanut butter powder (I use Naked PB powder) has only 50 calories and 1.5 grams fat, compared to 2 Tbsp. of traditional peanut butter which has 190 calories and 16 grams of fat. They both provide 6 grams protein and 2-3 grams of fiber per serving.

Whether using traditional peanut butter or peanut butter powder, look for a brand that has 0 grams of added sugar, and is free of hydrogenated vegetable oil which is highly inflammatory. Ideally, choose a variety that is made from only peanuts (or peanuts and salt). 

I like to use 2 tablespoons of Naked PB in this smoothie because not only is it free of added sugars and salt, it’s also tested for heavy metals which can be found in many powdered products and are toxic to our health.

Protein Powder 

Since kefir only has 10 grams of protein per serving, I also like to add 1 scoop of vanilla protein powder for an additional protein boost. It also gives the smoothie a really great flavor! 

I use Shaklee’s Life Shake soy protein powder, because it has 20 grams protein and 6 grams of fiber per serving, is low in added sugars (only 5 grams added sugar per serving), and is made with natural ingredients. It’s also gluten free, dairy free, and vegan. 

I also like Naked Nutrition vanilla protein powder and doTERRA’s vanilla protein powder which are similar in terms of nutrition and quality. 


Use ice to thicken your smoothie if desired. If using a frozen banana, I typically add 1 cup of ice. If using a fresh banana, I use 1 ½ to 2 cups of ice. 

How to Make It

This smoothie is so easy to make! Simply add all ingredients to the blender, and blend until smooth. 


I recommend drinking the smoothie immediately, as it thickens and becomes gelatinous if it sits out or is refrigerated. 

Green Smoothie topped with chia seeds

Green Smoothie (Peanut Butter Banana)

This green smoothie is packed with protein, fiber, and healthy fats to keep you full, plus loaded with nutrients and antioxidants. The combo of peanut butter and banana makes it taste more like a milkshake than a healthy smoothie!
Prep Time 10 minutes
Cook Time 0 minutes
Total Time 10 minutes
Course Breakfast, Drinks, Snack
Cuisine American, Mediterranean
Servings 1
Calories 430 kcal



  • 1 cup kefir plain
  • 1 banana frozen
  • 1/2 avocado optional
  • 1 cup spinach 1-2 handfuls
  • 1 tbsp ground flaxseed
  • 1 tbsp chia seeds
  • 2 tbsp PB powder or 1 Tbsp. peanut butter I use Naked Nutrition PB Powder
  • 1 scoop vanilla protein powder I use Naked Nutrition or doTERRA
  • 1 cup ice more if using fresh banana instead of frozen


  • Add all ingredients into blender and blend until smooth, scraping the sides about halfway through.
  • Add more ice to create thicker consistency, or add water for thin consistency.
  • Enjoy!


Calories: 430kcalCarbohydrates: 45gProtein: 30gFiber: 12g
Keyword Easy, Healthy
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