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.
Pam
What is the weight for the serving to equal the 211 calories?
Katrin Nรผrnberger
About 40 grams.
Magdalena
Hi Iโd like to know what kind of protein powder you use.
Thanks
Katrin Nรผrnberger
Hi Magdalena, I use Pulsin Whey Protein Powder, I get it from Ocado.
Jenn
Is a pea protein okay? I try to avoid Whey due to issue with dairy. I know that will add a bit to carbs but it's what I have and know I can stomach ๐
Katrin Nรผrnberger
I have never tried it, but it's worth a shot. I think they all behave similarly.
Dominic Hodges
Hi, I made these the other day and they have turned out very dry, not at all fudgey. I actually only cooked them for 20 minutes because I baked them in muffin cups instead of a baking tray.
Mine have come out at 3.6g net carbs according to Carb Manager which is a bit higher than I was hoping for, but also means I can't really put any sort of topping on them to help with the dryness.
They could really do with something like caramel between the two layers and/or a chocolate topping to moisten them up a bit, do you have any suggestions for that? I have 90% dark chocolate but I much prefer milk chocolate so don't really want to use that, especially as it will bump up the carb count a bit as well.
Katrin Nรผrnberger
I have a keto caramel recipe on my website, and you could make your own sugar free chocolate, too.
What a shame they turned out dry. It could have happened because your peanut butter was firmer than mine. When you buy a big tub, the top is always nice and soft, but if you don't stir it regularly, the bottom bits can get very firm. Also, if you bake it in individual containers such as muffin cups, consider reducing the oven time to as little as 12 -15 minutes as you would for cookies.
Dominic Hodges
Thanks Katrin, I did wonder about cooking time, but not until yesterday... I'll take a look at the caramel recipe. I've tried one before and it didn't work out too well.
Donna Read
Hello, I used Almond flour instead but kept to the same quantity as the Coconut flour. They turned out very dry, so much so that they just broke apart while slicing. They do taste nice though be them very hard to eat as they crumble up so much.
Wondering where I went wrong.
Katrin Nรผrnberger
Hi Donna, the reason could be that your peanut butter was firmer than mine. This would cause the end result to be drier. Another reason could be that your bars were flatter than mine. As a rule of thumb, the flatter a bake is, the less time it needs in the oven. I hope this helps and you can work out how to get your bars the perfect texture next time round.
SN07
Hi there,
I have not tried this recipe yet. I am just wondering based on the ingredients listed what is the net carb per slice?
Katrin Nรผrnberger
My nutrition panel always shows the total carbs and the fibre. For the net carbs, you deduct the fibre from the total carbs.
Karen Stinson
Where do you get Lily's? I live in France and can't even get them on Amazon.
Katrin Nรผrnberger
Hi Karen, I had a big batch brought over from the States. But when I run out, I just use the 90% chocolate by Lindt or make my own.
Susan Yakus
I tried these. They were delicious! I have Vanilla Protein Power on hand. Will that taste ok too? I also have Chocolate Protein Powder.
Katrin Nรผrnberger
Hi, you could use either but check if it contains any sugar or sweeteners first. Mine was unflavoured and you may have to adjust the sweetness.
Marjie Bass
Is it possible to double this recipe?
Katrin
Yes, I don't think that would be a problem! If you bake it all at once, it may take a little longer in the oven.
Avery
Just checking, the baking dish needs to be 5x6 inches? Thanks!
Katrin
Yes, that's the size of dish I used. If yours is larger, just build a divider from aluminium foil, otherwise your bars will be too flat.
Betsy
Can I use powdered peanut butter in this recipe?
Katrin
I think that powdered peanut butter is fat reduced so you would not achieve the same taste.
Rico
Looks like basically no carbs (figuring in the sugar alcohol). I like to try and preserve as muscle as I can while on Keto. For taste, would I have to alter the other ingredient for taste it I doubled the protein? If so, what do you suggest?
Katrin
That's a good question. You'd add quite a bit more powder, which may make the bars brittle and dry-tasting. I'd add just a little more if you want (amount will depend on how liquid your peanut butter is).