5 Best Fiber Supplements for Keto Diet [incl. How to Choose]

best fiber supplement for keto

There are several reasons why it’s very important to take special care about your fiber intake while on Keto.

To name one, constipation is probably the most common side-effect for people following the Ketogenic diet.

You might or might not know that it’s deeply connected to your fiber intake. Or to be more precise, the lack of it.

The solution for this issue is to simply increase your daily fiber intake, and, other than getting it through the food you eat, you can also do it through various fiber supplements.

Following in the article, we will thoroughly explain in what ways dietary fiber is able to improve your Keto diet, what are the advantages of using fiber supplements, and we will also review a few of the best quality fiber supplements on the market.

What is dietary fiber?

Dietary fiber is a plant-based nutrient which is a type of carbohydrate but, unlike other carbohydrates, it can’t be broken down into digestible glucose molecules.

Instead, it mostly passes completely intact through the digestive system while providing our bodies with many health benefits.

It can be classified into two categories: soluble and insoluble fiber.

  • Soluble fiber – Soluble fiber dissolves in water and forms a gel-like material. It is most known for its benefit of lowering cholesterol and blood glucose levels. Soluble fiber is found in foods like beans, apples, carrots, peas, oats, barley, and psyllium.
  • Insoluble fiber – Insoluble fiber, on the other hand, does not dissolve in water and passes through the stomach, small intestine and colon relatively intact. It speeds up the passage of food through our digestive system, which helps prevent constipation and maintain regularity. Insoluble fiber is found in foods like nuts, wheat bran, whole-wheat flour, and vegetables such as green beans, cauliflower, and potatoes.

Health Benefits of fiber

Both soluble and insoluble fibers have important health benefits.

  • Gut health – Your gut holds about 100 trillion friendly microbes that help us in many different ways. They represent a big part of our whole immune system. A recent study from 2017 has found fiber to be directly correlated to the function of our gut microbes. [1] Dietary fiber literally feeds those microbes and makes them thrive. The more food they have, the bigger their number gets.
  • Constipation – Dietary fiber, particularly the insoluble type of fiber, is most known for its ability to help reduce constipation. It does so by adding bulk to the stool, making its passage through the digestive system faster and smoother. 
  • Weight loss – Soluble type of fiber has been shown to slow down both the emptying of the stomach and the absorption of energy from foods. These effects slow down and delay the release of the appetite-stimulating hormone ghrelin, which helps you feel full and satisfied for longer and can indirectly lead to weight loss. 
  • Blood glucose – Even as early as 1990, studies have clearly shown that the viscosity of fiber is related to the reduction in postprandial blood glucose. For an example, a study published in the New England Journal of Medicine in 2000 has found that a high intake of fiber, particularly of the soluble type, improves glycemic control, decreases hyperinsulinemia, and lowers plasma lipid concentrations in people with type 2 diabetes. [2]
  • Cholesterol – Studies have also shown that soluble fiber may help lower total blood cholesterol levels by lowering the low-density lipoprotein, which is also known as “bad” cholesterol. [3] Other than cholesterol, studies have found that high-fiber diets may have other heart-health benefits, like reduced blood pressure and inflammation.

Why do you need fiber during Keto?

High-fat diets like Keto slow digestion and decrease GI (gastrointestinal) motility, which makes it especially important to get enough fiber in the diet.

Although, when following a Ketogenic diet, it is actually very common for people to neglect their daily needs of fiber in an attempt to not go overboard with carbohydrates. Which is understandable, since most of the fiber-rich foods are way too starchy to consume while on Keto.

A lack of fiber can lead to a lot of problems such as constipation, not being able to absorb nutrients from food, and poor digestion in general. These issues can make or break all of the hard work you’ve put in, and that’s why dietary fiber is considered to be a Keto staple.

This is why you need to take extra care for fiber during Keto, either through a fiber supplement or by consuming enough fiber-rich foods daily.

High-fiber foods vs. fiber supplements

There is no fiber at all in the main keto foods like meat, fish, poultry, eggs, dairy products, and healthy fats. Instead, it is mostly found in foods like beans, legumes, nuts, breads, grains, and some fruits and vegetables.

But unfortunately, on Keto, most of the fiber-rich foods are either strictly limited or completely forbidden because of their high-carb profile. For the average Keto dieter, the most popular sources of fiber are avocados, leafy greens and veggies like broccoli, spinach, celery, cabbage, and most nuts and seeds.

While all these foods should be a staple in everyone’s Ketogenic eating plan, to reach your daily needs of fiber, you need to eat a lot of them every single day. Which, in reality, is not always possible and convenient.

That’s where fiber supplements come into play. They are very convenient to use daily and on-the-go, and they make it very easy to get enough fiber – with a supplement, you don’t need to consume a ton of vegetables, you can just use the supplement once or twice a day instead.

Also, fiber supplements in powder form can be easily mixed in shakes and in most of cooking/baking recipes.

How much fiber do you need?

Most people don’t consume enough fiber daily. While the Institute of Medicine recommends a daily fiber intake of 38 grams for men and 25 grams for women, most people top out an average of 15 grams per day. [4]

If you don’t meet your daily needs of fiber, there are four key warning signs to watch out for: constipation, sudden weight gain, nausea, and tiredness.

If you, however, eat too much fiber, your body will begin to tell you to back off. Some of the symptoms of consuming too much fiber are gas, bloating, abdominal cramping, and loose stools or diarrhea.

How to choose a fiber supplement?

  1. Convenience – Fiber supplements come in two forms, powder, and pills (capsules). If you like cooking and you often cook various keto-friendly meals or do shakes in the blender, then going with the powdered version is probably better for you. The fiber powder will add bulk to your recipes, improve their texture and even the taste if it’s a flavored type of supplement. If you, however, have a busy schedule and don’t spend a lot of time in the kitchen, pills are the most convenient way to go.
  2. Go with safe well-known brands – In our opinion, it’s always worth it go for a brand that is already well-known and reputable in the industry. The product might be a little bit pricier than some other brands, but the peace of mind you get about its quality is worth it. And considering you are on Keto, a brand that claims their product is specifically made for a low-carb diet is a plus.
  3. Think of the type of fiber and ingredients used – Depending on your needs, one fiber supplement will be more suitable for you than another. All fiber is not created equal. If you lets say have constipation or diarrhea, a soluble type of fiber like psyllium husk powder is a great option. Psyllium husk powder is probably the most used and most popular fiber supplement at the moment. Unsoluble types of fiber, however, are best for constipation only and don’t help diarrhea at all. If you are looking to improve the state of your gut flora, a fiber like Inulin is most likely best for you. It’s a soluble, prebiotic type of fiber, which serves as food for your colon’s microbe population. But, be careful. Other than the fiber used, it’s also important to check for other used ingredients as well. There are some brands out there that don’t really care to cater to the low-carb community, and they use non-Keto stuff like Maltodextrin and Dextrose as fillers and preservatives. These products will probably do more harm than good, so always make sure to check the full ingredient list!
  4. In case you pick a powder, think of the taste – If you decided to go with the powder type, picking a supplement that tastes good is vital for you being consistent in using it daily. There are a lot of fiber supplements out there that taste really bad, so before buying make sure to check what other people think of it.

Best fiber supplements for Keto

1. Ancient Nutrition KETO Fiber Powder

KETO Fiber is a product formulated by Dr. Josh Axe, who is a well-known health-guru in the healthcare industry.

If you’ve ever looked up anything health related on youtube or google, there’s a good chance you’ve run into some of his content.

As the name suggests, it’s a Ketogenic-friendly supplement, and it features organic chia seeds, flax seeds, and cinnamon bark extract as the main sources of its fiber content.

Other than the fiber, it’s also boosted with coconut MCTs and several fermented herbs.

It’s gluten-, dairy-, and soy-free, and it’s sweetened with stevia leaf extract.

» Check the price of Ancient Nutrition Keto Fiber here

Taste: Neutral, earthy flavorMade of: Organic chia seeds, organic flax seeds, organic cinnamon bark extractServing size: 1 scoop (17g)Calories: 40 cal Fiber: 5g Net carbs: 2g Protein: 4g

The good

  • All of the ingredients are organic, natural, and keto (low-carb) friendly as well
  • Ingredients-wise, it’s a pretty solid fiber formula.
  • It contains only 40 calories per serving.
  • Has a good amount of both soluble and insoluble fiber per serving.

The bad

  • Personally, I think it tastes awful. But health doesn’t supposed to taste great?

2. NOW Psyllium Husk Powder

NOW Psyllium Husk Powder is made by Now Foods, a US-based company that’s in the healthcare industry since 1968.

It’s safe to say that NOW is the most well-known and reputable health supplement brand ever, and for a reason.

They have a very broad range of health products and supplements, always making sure quality is the top-most priority for each and every product.

The NOW Psyllium Husk Powder is made of only one single ingredient – Organic Psyllium Husk Powder. It’s a soluble type of fiber that comes from the husk of the seeds of the Plantago ovata plant.

now psyllium husks

Being a soluble fiber, it acts as a bulk-forming agent, making it very useful for cooking various keto-friendly recipes like almond flour bread or using it to make a delicious pizza crust.

» Check the price of NOW Psyllium Husks here

Taste: No flavor (natural psyllium husk taste)Made of: 100% Organic Psyllium Husk PowderServing size: 2 level tbsp (10g)Calories: 30 calories Fiber: 7g Net carbs: 1g Protein: 0g

The good 

  • The company behind this product is probably the most reputable and well-known brand in the US health supplements industry.
  • Made of only 1 single ingredient. Simple but efficient.
  • A really, really good product for relieving constipation. Just 1 tablespoon a day is enough for maintaining regularity in the bathroom.
  • Can use it in various baking recipes such as a keto-friendly bread or a pizza crust.

The bad:

  • Although it’s not that bad, it doesn’t have the best taste when taken on its own with water. Adding it to baking recipes or using another flavored liquid is completely fine on the other hand.

3. Sunergetic Psyllium Husk Capsules

The Sunergetic Psyllium Husk Capsules is another product that’s 100% Pure Psyllium Husk, but in the form of capsules. It’s made by a US-based company Sunergetic, which is in the health supplements industry for over five years now. All of their products are FDA approved and they are manufactured in a facility that adheres to Good Manufacturing Practices (GMP).

While the product is for sure top of the shelf in terms of quality, a big downside is that there is a very little amount of fiber per serving (2 capsules) – only 0.9 grams. So, if you want to get 5 grams of fiber from it, you’d need to chug down 11 capsules.

sunergetic psyllium husk fiber for keto

Also, because it’s in capsule form, it’s way more expensive than powder fiber. Just to compare, for the same price you can get about 6 times more in terms of quantity in powder form.

» Check the price of Sunergetic Psyllium Husk Capsules here

Taste: No flavorMade of: 100% Psyllium Husk PowderServing size: 2 Capsules Calories: ~10 cal Fiber: 0.9g Net carbs: 1.1g

The good

  • Capsule form – convenient to use at all times and on-the-go
  • Made of only 1 single ingredient – Psyllium Husk Powder

The bad

  • Pretty expensive in terms of the total quantity of fiber you get

4. Heather’s Tummy Fiber CAN

Heather’s Tummy Fiber is made and sold by Heather Van Vorous, an IBS (Irritable Bowel Syndrome) sufferer since age 9, who decided to use her thirty years of experience in dealing with IBS to help others. She is the CEO of Heather’s Tummy Care, founded in 2001.

The fiber is one among several products on the website specifically made to help with IBS symptoms.

It has only one ingredient, 100% Organic Acacia Senegal, a 100% soluble type of fiber which is made from the sap of the Acacia Senegal tree.

Overall, the powder mixes pretty well in shakes and baking recipes. If you happen to suffer from IBS yourself, her website also has a ton of free info like an IBS diet and recipes, IBS treatments and diagnosis etc.

» Check the price of Heather’s Tummy Fiber here

Taste: No flavor Made of: 100% Organic Acacia SenegalServing size: 2.5gCalories: 10 cal Fiber: 2g Net carbs: 0g

The good

  • Made of only 1 ingredient – Organic Acacia Senegal powder
  • Specifically made for IBS sufferers
  • The powder mixes pretty well overall
  • 100% organic ingredients, free of GMO, fillers, sweeteners

The bad

  • It’s a 100% soluble type fiber product, not very ideal if you are looking for a complete fiber supplement (soluble and insoluble)

5. Meta Mucil Psyllium Fiber Capsules

The Meta Mucil Psyllium Fiber Capsules are another 100% Natural Psyllium Husk product in the form of capsules, made by the company Metamucil.

Metamucil has been around since 1934, and the company claims it’s the #1 doctor recommended fiber brand for over 80 years now.

The capsules have only one ingredient, Natural Psyllium Husk powder.

But, as it is the case with the other capsule types of fiber supplements, a big downside is that the amount of fiber you get per capsule is very, very low.

With these, there are only 2 grams of fiber per 5 capsules (0.4g per capsule).

meta mucil fiber capsules for keto

The product’s recommended intake is 5 capsules 4 times daily. While it may be convenient that the product is in capsules form, it’s not very convenient to chug down 20 of them a day.

» Check the price of Meta Mucil Fiber Capsules here

Taste: No flavor Made of: 100% Natural Psyllium fiberServing size: 5 capsulesCalories: 10 cal Fiber: 2g Net carbs: 0g

The good

  • Made of 1 single ingredient – 100% Natural Psyllium fiber
  • Capsule form – convenient to use at all times and on-the-go

The bad

  • Capsules are physically big


In our opinion, powder form fiber supplements are superior to the ones in capsules. With powder, you get way more bang for the buck, and personally, it’s way easier to consume a teaspoon of the fiber in a glass of liquid rather than chugging down 20 capsules.

We believe that the NOW Foods Psyllium Husk powder is the overall winner of the roundup in the previous section.

For one, the only ingredient the product has is 100% Organic Psyllium Husk powder. Nothing else. No fillers, preservatives, GMO ingredients, and it’s also gluten-free. It’s completely Keto-friendly.

Secondly, as compared to the Keto Fiber and Heather’s Tummy Fiber, the Now Foods fiber mixes the best in liquid by far. And also, very importantly, it has virtually no flavor at all – unlike the Keto fiber one, which tasted really bad – so it won’t change the flavor in cooking recipes and you can easily consume it in a glass of water.

And if you really prefer capsules over powder, they have a capsule form product as well.

Lastly, as we discussed in the review earlier, Now Foods is a trusted company for years and a top of the shelf brand when it comes to these kinds of supplements, which was the icing on the cake (a Keto cake, don’t judge!) for our decision. 


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