What are the Best Sources of Fiber on a Keto Diet?

  • Author: Katie
  • Date: October 9, 2022
  • Time to Read: 8 min.

Getting enough fiber on a keto diet can be a contentious subject, but it does not need to be, in this article we will take you through why you need to be mindful of what fiber you are eating on a keto diet and the consequences of not eating enough fiber vs eating too much. Most importantly, we will take you through our favorite low carb, high fiber food options and even how to incorporate these into your keto lifestyle. What are you waiting for read on…!

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Keto is a way of eating which focuses on the reduction of carbohydrates (carbs) and increase in fat in your diet which results in your body going into a state called ketosis.

It is different from a low-carb diet in that keto restricts the number of carbs consumed even lower than that of a low-carb diet.

Best Sources Of Fiber On Keto

Keto involves our bodies entering a metabolic state known as ketosis. In our non-keto diet, a lot of the fiber we consume comes from the high carbohydrate foods that we eat.

When you transition onto a keto way of eating, these carbohydrates are largely eliminated from your diet.

This means that the sources of fiber that you are using, you are no longer having.

Some people that are new to a keto lifestyle may struggle to get enough fiber (roughage) in their diet, which can cause several different issues which we will discuss below.

Not getting enough fiber in your diet is one of the main criticisms of keto and low-carb diets. However, this definitely does not have to be the case.

Why do we need Fiber in our Diets?

Fiber is what keeps everything moving through (and out of) our digestive system.

Too little fiber is not good for your health as it is the fiber that feeds the good bacteria in your gut, this is what makes your bowel movements comfy and ensures good digestive health.

Fiber comes in two forms soluble and insoluble.

Soluble Fiber

Soluble fiber dissolves when it comes into contact with liquids and forms a gel-like substance in the digestive tract.

As this gel-like substance is formed in your gut, it swells in size making you feel fuller and more satisfied.

Soluble fiber can slow the absorption of sugar into the blood and as such can help improve and regulate  blood sugar levels

Insoluble Fiber

Insoluble fiber does not dissolve in the same way as soluble fiber.

Insoluble fiber stays in its original form and does not dissolve like soluble fiber (hence its name!).

Insoluble fiber is commonly known as ‘roughage’.

Roughage helps the colon move and dispose of waste (in simple terms, it helps the poop move through and out!).

If you have a condition such as diverticulitis, you will appreciate how important it is to get enough fiber in your diet as good gut health helps your immune system as well as your bowel movements.

Here we will quickly round up what happens to your body if you do not get enough fiber, and what happens if you get too much.  

What Happens if I Don’t Eat Enough Fiber?

  1. Constant Bloated Feeling – Bloating is caused by the gas that is released from certain foods. Food products that are likely to contribute to this bloating feeling are; dairy, alcohol, and carbohydrates. When you are eating enough fiber, these gasses will be expelled from your body
  2. Constipation or Irregular bowel movements -As discussed above, one of the main roles of fiber is to keep our bowels working efficiently, and our colon healthy. It helps remove toxins and stools from our bodies. If you don’t have enough fiber in your diet, this process will be slowed down and will result in either irregular bowel movements, loose stools, or even constipation, which can become very painful
  3. You are gaining more weight. Fiber helps you to regulate insulin levels in the body. It also helps bind the starches in the body. This helps to break down carbs in the body, which helps to regulate blood sugar levels. When your blood sugar is not regulated, this is when you have cravings for sugar-laden foods, which will see you gain weight. Fiber helps to combat this.
  4. Higher Blood Pressure – When eating an appropriate level of fiber, it can help to reduce blood pressure levels. If you’re not eating enough fiber, your blood pressure may increase (hypertension), which can lead to symptoms of tiredness, headaches, and chest pains. Getting enough fiber in your diet will help prevent this.
  5. Acne -As we have discussed above, fiber removes toxins from our body, if toxins remain in the body, the effects can normally be seen in the skin. The skin is the largest organ in the body, so it can often give you a good indication if something is not right on the inside. Dull, acne-prone skin can be a sign that you are not getting enough carbs on your keto, low-carb diet.

As you can see, there are a lot of risks associated with too few grams of fiber, however, there are also risks associated with eating too much fiber, these are discussed below.

What Happens if I Eat too Much Fiber?

Eating too much fiber can have as many negative impacts on your body as eating too little. Some of the symptoms overlap with eating too little.

The most common symptoms of eating too much fiber are:

  • Bloating
  • Excessive Gas
  • Uncomfortable feeling in the stomach
  • Stomach cramps
  • Constipation or diarrhea
  • Dehydration
  • Weight gain or loss
  • Nausea

So What Amount of Fiber is Optimal for a Keto Diet?

The average adult should eat between 20-40 grams of fiber a day according to the UK’s National Health Service. 

Too much fiber is defined as over 70 grams of fiber. 

This can be broken down further into the recommendations for various demographics;

  • 25g per day for adult women
    • Women over 50 years – 21g
    • more fiber is required when pregnant or lactating, a minimum of 28 grams.
  • 38g per day for adult men
    • Men over 50 years – 30g

For children, the optimum amount of fiber is commonly calculated by adding 5 to their age. I.e. a 10-year-old child would require in the region of 15 grams of fiber a day (10 + 5 =15)

Why do some people not get enough fiber when eating a Keto Diet?

Some people do not naturally eat a lot of vegetables in their pre-keto diet, so it may take them a while to get used to eating them on a keto diet.

Also, a lot of people will stay away from fruits as they have read that they are high in sugar.

As a result, they become confused as to what they can eat, so stay clear of a lot of foods.

In this article, we will take you through what are your best options for eating a keto or low-carb diet and still getting enough fiber in order to maintain your gut health.

Is Fiber a Carbohydrate?

Despite the majority of fiber sources being carbohydrates, fiber does not raise blood glucose levels in the case way as carbs do.

That is why many people eating the keto diet will only deal with ‘net carbs’.

Net carbs are the total amount of carbohydrates in a food minus the digestible fiber. Check out our article on net carbs for more information on how to work this out and, more importantly, how to understand food labels.

What are the best health sources of fiber for a Keto Dieter? 

There are a number of fiber-rich foods that contain a low amount of net carbs. These will not kick you out of ketosis and will help keep your digestive system running smoothly!

List of High Fiber, Low-carb foods

There are a number of non-starchy vegetables that are low in carbs and high in fiber. General green vegetables that are grown above-ground fall into this category.

Here is a list of our favorite high-fiber, low-carb foods by category;

Nuts & Seeds

  • Pecan Nuts
  • Almonds (including Almond Butter)
  • Ground Flaxseed – there are almost no digestible carbohydrates in flax seed. They are around two thirds insoluble fiber, one-third soluble fiber
  • Pumpkin Seeds
  • Psyllium Husk

Fruit & Vegetables

  • Avocados
  • Chia Seeds – similar to flax seeds, these are high in insoluble fiber which will keep you regular, keep your blood sugar regulated and keep you feeling fuller for longer. Chia seeds really are a superfood!
  • Asparagus
  • Broccoli
  • Brussel Sprouts
  • Spinach
  • Swiss Chard
  • Cauliflower
  • Bell Peppers
  • Courgette (Zucchini)
  • Aubergine (Eggplant)
  • Mushrooms
  • Coconut (raw or unsweetened and inc coconut oil and coconut flour)
  • Raspberries
  • Strawberries
  • Blueberries


  • Cocca Powder

If you are not used to eating fiber in your diet, don’t suddenly start eating a larger amount in one go, gradually increase day by day and ensure that you remain hydrated to ensure that the fiber has enough liquid to mix with.

Smoothies can be a great way of adding veg, fruit, coconut milk, or chia into your daily routine. Or why not add coconut oil to your daily coffee?

Are Fiber Supplements Necessary for a Keto Diet?

Let me be clear, fiber supplements are not necessary for a keto diet, anybody that insists that this is the case is only trying to sell you something!

You should be able to get more than enough fiber naturally through the foods you consume.

If you are struggling to get enough fiber through your regular diet, fiber supplements may be an option for you.

They can be a great will to add additional nutrients into a diet, however, they should be used as their name suggests, as a supplement, you really should try and get your fiber from fiber-rich foods which we have listed above.

There are varying qualities of supplements out there on the market, so ensure that if you chose to take this avenue, only buy supplements from a reputable supplier. 

How can I Track How Much Fiber I am Eating?

We have spent this whole article telling you why you need fiber in your diet, the consequences of not getting enough fiber, and where to get that fiber from.

What we haven’t helped you with is how to know what ’25 grams’ of fiber actually looks like.

The easiest way to do this is by using a tracking app like MyFitnessPal. There are a lot of different tracking apps out there, but I have found this one to be the most reliable.

Just ensure that you enter the brand of food that you are consuming to get an accurate recording of what you are eating. This will give you an accurate understanding of not only your macros (fat, protein, and carbs) but also the nutritional value of the foods that you are eating

Final Thoughts

That has been a bit of a whirlwind tour of fiber, the health benefits of eating the right amount of fiber are clear. Yes, you do need to be mindful of what you are eating on a keto diet, including your fiber intake, however, there are plenty of fiber-rich, keto-friendly foods out there for you to choose from, use your imagination as to how you will incorporate these into your keto lifestyle.

What are your favorite keto-friendly high-fiber foods? What inventive ways have you found for incorporating these into your keto diet? Let us know in the comments below!

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