Skip These Fibers & you'll Feel the Consequences!

This article is dedicated to:

🔹 My creatures of habit who eat (mostly) the same foods every day

🔹 Anyone eating less than 5 servings of veggies & fruits per day

🔹 Those who follow a Keto, Low Carb, Carnivore, Paleo, Autoimmune Paleo (AIP), low FODMAP, low lectin, low sugar, OR other diet that restricts certain carbs.

Sure, having routine can be a beautiful thing in helping to keep us on track. And specific diets can have unique benefits such as low FODMAP reducing bloating and related symptoms, or Paleo-style diets can be great for reducing inflammation, improving immune function, boosting energy, and enhancing quality of life (1,2,3).

However, if you’re not including certain key foods, these eating patterns can backfire over time—leading to digestive issues, fatigue, poor mental health, and even weight gain (4,5).

At first, these issues may not surface, but prolonged adherence to these diets without specific nutrients (keep reading for details) increases the risk of many adverse health effects (4,5).

KEY CONCEPT: 

Fibers and polyphenols—naturally occurring plant compounds—are essential for feeding beneficial gut bacteria. We have thousands of bacterial species that live in our gut! 

Each type of fiber feeds different bacterial species, and research has discovered that the diversity of microbial species is one of the main drivers of our health (4,5,6)!

These microbes influence everything from digestion and metabolism to immune function and hormone balance.

The Fiber Secret

There are critical fibers and polyphenols found in foods excluded on paleo, AIP and keto—such as seeds, nuts, grains, and legumes—that literally feed your beneficial gut bacteria (1,2,3). And trust me, you want those little guys thriving!

You may have heard of soluble and insoluble fiber, but did you know there are actually dozens of fiber types like soluble gums, resistant starch, and galactooligosaccharides (6)?

Nuts, seeds, grains, and legumes are rich in these unsung fiber heroes. Since each fiber type plays a unique and crucial role in gut health, it’s essential to eat a variety of plant-based foods (1,2). Eating the same foods every day reduces our gut microbial diversity!

The good news? There’s a way to do paleo-style and keto diets the right way and get the fiber your gut microbiome needs!

Fiber Foods You Must Include:

Here are the key fibers and prebiotics missing from paleo-style and keto diets—and the best AIP and keto-friendly alternatives to keep your gut healthy:

🔹 Soluble Gum Fibers –

Typically in almonds and chia seeds.

AIP-friendly sources: okra, aloe vera, certain squashes (9).

Keto-friendly sources: konjac root (miracle noodles), okra, aloe vera.

🔹 Resistant Starch –

Found in oats, legumes, and rice.

AIP-friendly sources: plantains, sweet potatoes (must be cooked & cooled), green-tinted bananas (10).

Keto-friendly sources: Honestly, there aren't many! Konjac root (miracle noodles) and tiger nuts contain small amounts.

Resistant starch plays a vital role in gut health by promoting the production of short-chain fatty acids (SCFAs) like butyrate, which helps maintain a healthy gut lining, reduce inflammation, and support metabolic health.

Note: Different types of resistant starch exist, with Type 1 being primarily found in seeds and grains—foods excluded on AIP. This highlights the importance of a reintroduction phase to restore gut microbial balance and access the full spectrum of fiber benefits.

🔹 Beta-Glucans –

These fibers are found in oats and barley.

AIP-friendly and keto-friendly source: mushrooms (11).

Beta-glucans are crucial for immune regulation, cholesterol balance, and gut health. Research highlights their role in modulating immune function, reducing inflammation, and supporting a healthy microbiome. Regular intake of beta-glucan-rich foods, like mushrooms, may enhance gut barrier integrity and contribute to overall metabolic health (11).

🔹 GOS Fibers –

Mainly in legumes.

AIP-friendly and keto-friendly sources: artichokes, asparagus, dandelion greens (12).

GOS fibers are like fuel for good gut bacteria that help to balance blood sugar, improve cholesterol levels, and support a healthy weight. For those with autoimmunity, this is key—stable blood sugar and a well-functioning metabolism can help keep inflammation in check and support overall immune balance. Adding GOS-rich foods to your diet may be a simple way to improve both gut and metabolic health (12).

🔹 Lignans –

Found in flaxseeds, legumes, and whole grains.

AIP-friendly sources: cruciferous veggies (broccoli, kale, cabbage, Brussels sprouts), garlic, apricots (8).

Keto-friendly sources: flaxseeds, cruciferous veggies, garlic

Lignans are polyphenols that act as prebiotics, supporting gut bacteria and can do wonders for balancing hormones (especially estrogen!) and immune function (8).

How to Put This Into Practice:

If you follow a keto or low carb diet, consider expanding your diet, or at least doing cycles on and off.

If you follow a low FODMAP diet it is essential you address the underlying imbalance so you can return to eating otherwise healthy foods that contain FODMAPs. Because if you bloat with these fibers it could indicate bacterial or fungal overgrowths—you may need to work with a practitioner to restore gut balance first.

If you follow a paleo or AIP diet, once your immune system calms down and your health improves, it’s critical to begin a reintroduction phase to expand your diet.

✅ For example, here's my approach with autoimmune clients:
I start them with an AIP protocol for at least 6 weeks, then strategically reintroduce small amounts of the following to see which are tolerated:
✔ Seeds
✔ Nuts
✔ Gluten-free ancient grains
✔ Pre-soaked, pressure-cooked legumes

How do I decide what to reintroduce first? I use lab testing + symptom tracking to personalize the process.

Long-term success for those with an autoimmune condition usually looks like this: Use the AIP diet as your base, with your safe reintroduction foods sprinkled in. This approach has been highly successful for my clients!

Did this info trigger more questions for you, or is there another topic you’d like to hear more about?  >> Submit your request to this form on my website <<

References: 

1. Pardali EC, Gkouvi A, Gkouskou KK, et al. Autoimmune protocol diet: A personalized elimination diet for patients with autoimmune diseases. Metabol Open. 2024;25:100342. Published 2024 Dec 30. doi:10.1016/j.metop.2024.100342
2. Abbott RD, Sadowski A, Alt AG. Efficacy of the Autoimmune Protocol Diet as Part of a Multi-disciplinary, Supported Lifestyle Intervention for Hashimoto's Thyroiditis. Cureus. 2019;11(4):e4556. Published 2019 Apr 27. doi:10.7759/cureus.4556
3. Konijeti GG, Kim N, Lewis JD, et al. Efficacy of the Autoimmune Protocol Diet for Inflammatory Bowel Disease. Inflamm Bowel Dis. 2017;23(11):2054-2060. doi:10.1097/MIB.0000000000001221
4. Leeming ER, Johnson AJ, Spector TD, Le Roy CI. Effect of Diet on the Gut Microbiota: Rethinking Intervention Duration. Nutrients. 2019;11(12):2862. Published 2019 Nov 22. doi:10.3390/nu11122862
5. Grace-Farfaglia P, Frazier H, Iversen MD. Essential Factors for a Healthy Microbiome: A Scoping Review. Int J Environ Res Public Health. 2022;19(14):8361. Published 2022 Jul 8. doi:10.3390/ijerph19148361
6. Cronin P, Joyce SA, O'Toole PW, O'Connor EM. Dietary Fibre Modulates the Gut Microbiota. Nutrients. 2021;13(5):1655. Published 2021 May 13. doi:10.3390/nu13051655
7. Mummert A, Esche E, Robinson J, Armelagos GJ. Stature and robusticity during the agricultural transition: evidence from the bioarchaeological record. Econ Hum Biol. 2011;9(3):284-301. doi:10.1016/j.ehb.2011.03.004
8. Álvarez-Caballero JM, Coy-Barrera E. Lignan. In: Antioxidants Effects in Health. 2022. ScienceDirect. Accessed March 1, 2025. https://www.sciencedirect.com/topics/nursing-and-health-professions/lignan
9. BeMiller J, Whistler R, Chen CC. Aloe, chia, flaxseed, okra, psyllium seed, quince seed, and tamarind gums. Materials Science, Agricultural and Food Sciences. 1993.
10. Patterson MA, Maiya M, Stewart ML. Resistant Starch Content in Foods Commonly Consumed in the United States: A Narrative Review. J Acad Nutr Diet. 2020;120(2):230-244. doi:10.1016/j.jand.2019.10.019
11. Cerletti C, Esposito S, Iacoviello L. Edible Mushrooms and Beta-Glucans: Impact on Human Health. Nutrients. 2021;13(7):2195. Published 2021 Jun 25. doi:10.3390/nu13072195
12. Kaur AP, Bhardwaj S, Dhanjal DS, et al. Plant Prebiotics and Their Role in the Amelioration of Diseases. Biomolecules. 2021;11(3):440. Published 2021 Mar 16. doi:10.3390/biom11030440

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