Why spend money on expensive energy bars when you can make this easy low carb protein bar recipe with only 5 simple ingredients! These sugar free protein bars are chewy and fudgy yet they stay firm at room temperature.

Protein bars boost your energy after a workout and they're a fat-fuelled, protein-rich snack if you need a pick-me-up in between meals.
The main ingredient of this gluten-free, keto protein bar recipe is peanut butter. Peanut butter already has a high protein content, which I'm boosting with additional protein powder.
I experimented quite a bit with this recipe, because originally I wanted to create a no-bake protein bar. However, no mix was sufficiently firm at room temperature whilst still fudgy and chewy. I did not want to coat the whole bar in chocolate only to get around that issue.
The solution? 25 minutes in the oven. Yes, a little bit of baking produces delicious sugar free protein bars that you can carry around all day in your handbag until hunger strikes!
Also try my high protein banana bread.
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Ingredients
Here are the ingredients you'll need:

- Peanut Butter - Must be soft and easy to scoop. Give it a good stir if necessary - especially in larger pots it tends to settle on the bottom of the jar and becomes hard. Also, check the label when buying peanut butter to make sure it does not contain added sugar! I like to use the Meridian brand - it contains 100% peanuts and nothing else.
- Protein Powder - I used unflavoured whey protein powder by Pulsin.
- Coconut Flour - to thicken and bind the bars.
- Granulated Sweetener - The sugar substitute you can see in the image above is golden Lakanto, which is an erythritol monk fruit sweetener blend. It is a brown sugar replacement. Xylitol or allulose will also work.
- Cocoa Powder - Unsweetened, for the chocolate layer.
See the recipe card for full information on ingredients and quantities.
Instructions
It's really simple to make this recipe! My homemade sugar free protein bars have a peanut butter layer and a peanut butter chocolate layer.
Scroll down to the recipe card for ingredient amounts, the detailed method and nutrition information.

STEP 1
Put the ingredients for the base and the top layer in separate bowls.

STEP 2
Mix the ingredients with a fork and knead with your hands until you have a smooth dough.

STEP 3
Line an oven-safe container with parchment paper. The mixture fills a space of 5 x 6 inches. Fill in first the peanut layer, then the chocolate peanut layer.

STEP 4
Bake the bars in the preheated oven on the middle shelf. They are done when the top does not glisten any more and has set while the edges are beginning to brown.
Then, let the low carb protein bars cool fully before you cut them. They will be fragile and soft while hot, but firm up as they cool.
Chef Katrin's Tips
#1 The peanut butter must be soft! Always stir it in the pot before you use it. Over time, peanut butter separates naturally.
#2 You can use crunchy or smooth peanut butter in this recipe. The bars with crunchy peanut butter can crumble a little when you cut them. For razor-sharp edges, I recommend using smooth peanut butter.
#3 Your dish is larger than 5x6 inches? No problem. Simply fold a bit of aluminium paper and use it as a separator. That way, you can use only part of your casserole dish. The mixture does not spread.
Variations
Almond flour - It's possible to use almond flour in place of the coconut flour. You may need to use 3 tablespoons of almond flour because it is less absorbent than coconut flour.
Dairy-free protein bars - Replace the whey protein with pea protein powder or another dairy-free protein powder. Note that I have not tried this yet - but it should work just as well.
Add flavor - Add 1 teaspoon of cinnamon for a taste variation or a pinch of sea salt.
More Chocolate - Stir a handful of sugar free chocolate chips into the mixture. Or, drizzle melted chocolate over the bars after they have cooled down.

Recipe FAQs
I do not recommend it. This would make the bars dry and brittle.
Yes, the recipe works with vanilla protein powder or chocolate protein powder.
The main reason why peanut butter protein bars turn out dry is that the peanut butter used was too firm. Always stir it before using to ensure it contains plenty of oil. Also, choose a natural peanut butter without additives such as palm oil. Another reason could be that the bars were flatter and therefore require less time in the oven.
Shop-bought low carb protein bars are convenient, but they are expensive. Plus, many contain additives to extend shelf life, questionable sweeteners and inflammatory vegetable oils. I've never sampled one that actually tastes good.
Storage
The bars keep on the kitchen counter for a couple of days and a good 7 days in the fridge.
You can also freeze them for up to 3 months.
More Low Carb Bars
- Keto Peanut Butter Bars2 Hours 15 Minutes
- Easy Keto Granola Bars30 Minutes
- Keto Twix Bars (Sugar Free)45 Minutes
- Keto Snickers Bars55 Minutes
More Keto Peanut Butter Recipes
- Low Carb Keto Peanut Butter Cookies15 Minutes
- Keto Peanut Butter Cheesecake4 Hours 15 Minutes
- Sugar Free Peanut Brittle (Keto)22 Minutes
- Keto Peanut Butter Mug Cake4 Minutes
Tried this recipe? Give it a star rating below!
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Recipe

Low Carb Protein Bars Recipe (Peanut Butter)
from Sugar Free LondonerNote: The servings slider only changes the first amount in each line and not any subsequent amounts. Please make your own calculations where necessary.
Ingredients
Base Layer
- ยฝ cup / 130g peanut butter unsweetened, soft
- 1 ยฝ tablespoon coconut flour
- 1 tablespoon protein powder
- 1 ยฝ tablespoon granulated sweetener
Top Layer
- ยฝ cup / 130g peanut butter soft
- 1 tablespoon cocoa powder unsweetened
- 1 ยฝ tablespoon granulated sweetener
- 1 tablespoon protein powder
- 1 ยฝ tbsp coconut flour
Instructions
- Preheat the oven to 175 Celsius / 350 Fahrenheit.
- Put the ingredients for the base and the top layer in separate bowls and mix with a fork, then knead with your hands to combine.
- Line an ovenproof dish with parchment paper. Spread the base layer, then add the top layer to fit a space of approximately 5 x 6 inches.ย
- Bake for up to 25 minutes. The bars are ready when the top has set and is beginning to brown around the edges. Remove and let cool to room temperature before cutting.
Notes
Nutrition
First published in March 2019. Republished with more information and tips in February 2024.
kostas
Nice and easy bars thank you
Helen Tomlinson
Just made these, waiting for them to cool before I cut them, smells delicious
Orly
These are delicious! Not a fan of coconut and was worried that the flavor would be strong, but not at all. Will definitely try crunchy peanut better next time - or can I just add some chopped nuts? Thanks for a great recipe!
Mary
I prefer no chocolate so can I just double the base layer to make them?
Katrin Nรผrnberger
Of course!
Mary
Would it be possible to use peanut butter powder to reduce the fat?
Katrin Nรผrnberger
I don't think so because they'd just be dry and brittle.
Mary
I meant if I reconstituted the peanut powder to with water per instructions? Are coconut flour and almond flour interchangeable?
Thanks
Katrin Nรผrnberger
As a rule of thumb, you'll need to use about 3 x more almond flour than coconut flour. It is less absorbent. As for the peanut powder, you'd have to try it out and see whether it works. I have never used it. But since you'd be replacing fat with water, my guess is that the bars may turn out dry.
MerlesGirl
What kind of protein powder? I don't know much about them. Can you recommend a few brands perhaps?
Katrin Nรผrnberger
Most of the time, I use Pulsin.
aidan
Hi, I'm new to keto so only learning. After reading the nutrition info do these bars work out roughly 40g each and 2 net carbs?
thank you
Aidan
Katrin Nรผrnberger
Hi Aidan, yes, these bars are 2g net carbs per bar. I did not weigh them.
aidan
Sorry Katrin, I thought I saw somewhere they were 40g each. I just made them but rather than make in a tray I used little cup cases to make individual portions. I always find that peanut butter no matter the brand is always a little bit clawing and coats the mouth and makes things dry at times. I found these to be a little dry (maybe under baked as took them out after 20 mins) but very very tasty. I love lots of things with peanut butter and these were delicious and will definitely be making them again. I also topped a couple with a little chocolate and god help me I could 3 or 4 at a time lol...Thank you
HEATHER VIRGINIA PETERSEN
pretty good and very easy to make!
Susan
What about powdered stevia? I'm type 1 diabetic so powdered stevia works best for me but confused on the conversion. Ty in advance!
Katrin Nรผrnberger
Hi Susan, you can use any sweetener as long as it is a 1:1 sugar substitute. It should say on the pack. I've had a few powdered stevia brands that are twice as sweet as sugar, so be sure you're not using too much.
Susan
Thank you!
Susan
What would the substitute be if I use almond flour instead?
Katrin Nรผrnberger
Use 3x more almond flour than coconut flour.
Damian
Hi, for the base recipes said granulated erythritol, is necessary grind it or not? I wish to do this bars asap, thank you.
Katrin Nรผrnberger
It's not necessary to grind it. But you can use powdered sweetener if you prefer. Both work just as well. I used a brown sugar alternative that is granulated.
Diana
Can I assume that the sugar listed is actually sugar alcohols since you are not using any added sugars? Thank you!
Katrin Nรผrnberger
No, I actually don't include the sugar alcohols at all because they are not processed by our bodies, making them essentially zero carb. The sugars you're seeing are from the other ingredients. Most foods contain some sugars from carbs.
Alex
These sound great! Can I use collagen powder in your recipe instead please? If so, same quantity as the protein powder?
Thank you for reading x
Katrin Nรผrnberger
Hi Alex, I have never tried the recipe with collagen powder. I think the taste and also the texture will be different. Not sure whether it would work.