WHAT is RESISTANT STARCH? and What are the best sources?

I may receive a commission if you purchase through links in this post. I am not a doctor; please consult your practitioner before changing your supplement or healthcare regimen.

Resistant starch (RS) is most notably found in tiger nuts and green plantains (see this recipe) and certain foods that have been cooked and cooled, like legumes, grains and potatoes. The starches are called resistant because they resist being digested in the small intestine. They remain intact to become food for the good flora located in our colon. This is a great discovery and I’d like to discuss how it can impact dietary choices, depending on our health situation.

Ironically, since resistant starch advocacy is now popular among Paleo healthcare practitioners, RS can be found in legumes and whole grains. I respect these practitioners for their open-minded pursuit of what heals the body. Paleo functional doctors seem to be leading the way in autoimmune research and treatment. Their anti-grain dogma is not preventing them from understanding the role and importance of RS.


They are pointing their patients to these starchy sources: green bananas, green plantains and what are called retrograded foods, those that have had their starch cooked and then cooled, rendering it resistant.

Examples of prepared foods that contain resistant starch due to retrogradation are potato salad, sushi rice, cold bean salad, even pasta salad.ย  All of these foods could likely be dressed in part with apple cider vinegar, which is advised, since vinegar is said to assist in the digestion of RS into butyrate. (Read more about butyrate and its role in colon health in my Food Renegade article, Resistant Starch: Healthy or Not.)

Cooked and cooled (RS3) foods can also be reheated! Think refried beans or chili made ahead of time, chilled and then reheated, or cooked al dente pasta put in the fridge and then reheated briefly in salted boiling water, reheated mashed potatoes (or see these yummy Smashed Potatoes) and leftovers in general. Yes, leftovers can be healthier than the original meal!

Very green plantains are another good source of resistant starch. Organic plantains are easy for most of us to source and they’re a whole food. Plantain flour can also be stirred into water or a smoothie.

What do you do with fresh green plantains? You dehydrate them. Here’s a recipe for either crackers orGreen-Plantain-Chips for resistant starch fruit leather. If you cook green plantains a lot of the resistant starch is lost. So these recipes keep the fruit raw, (which is not delicious on its own). Here’s another super yummy recipe for Brownie Bite Cookies!, full of RS.

Surprisingly, most advocates for increasing RS in one’s daily diet recommend a factory-made food, Bob’s Red Mill Potato Starch, working up to two to four tablespoons a day! I don’t agree with this approach.

The goal for restored health involves getting away from factory-made foods and having a whole food diet. Potato starch may feed good bacteria; but there are plenty of whole foods that do that too.ย  What potatoes does Bob use to make that starch? (Hint: they’re not organic and potatoes always make the Dirty Dozen list of most contaminated foods.)

A couple of other great grain-free options? Cassava flour (find it here). Cassava makes great baked goods, like these muffins or even in this hot chocolate. Tigernuts and tigernut flour are great! Here’s a Tigernut “Bran” Muffin. Jerusalem artichokes are another good source; fermenting them is ideal.

Health is not bought with convenience foods. Homemade food makes us feel better in more ways than one. (I like to make a big batch of resistant starch muffins each week, so I have a source of RS each day that’s easy to grab.)


All RS advocates warn that excess gas results from the initial introduction of this new food, and lasts for about two weeks. Most who’ve responded to blog forums on this topic say it subsides over time as the gut flora get used to their new food. I can now attest to this myself, having phased off of the GAPS diet and introduced multiple sources and quantities of RS. Start with 1 teaspoon to 1 tablespoon of resistant starch daily. See how your gut and bowels respond; and then proceed accordingly.

I appreciate the healthcare practitioners who counsel a slow introduction of RS-containing foods and are mindful of proper pre-digestion techniques.

We cannot prescribe in a tunnel. We must be aware of whole nutrition and traditional pre-digestion methods.

The majority of RS proponents do not themselves know about phytic acid and enzyme inhibitors; so they are not teaching proper soaking and sprouting. These sites on resistant starches are blindly recommending whole grain bread and brown rice, with no knowledge of sprouting or soaking grains, making it just one more fad, the latest thing, done without full understanding of foods and how they digest.

When this happens it is a blind leading the blind scenario and sadly, major health problems can ensue. Leaky gut gets worse when it’s exposed to whole grains that haven’t been pre-digested! So, if you’re interested in incorporating grain or legume-sourced RS, make sure to soak your grains or legumes properly first.


If your health is good or your leaky gut is mostly healed, if you do the Paleo diet or AIP, resistant starches may be something you want to try. Those on the GAPS diet should not eat these or any starches. They can be challenged if total healing is suspected. In the meantime, GAPS patients can enjoy prebiotic foods like leeks and onions, not cooked too long, to protect the prebiotic qualities. Fermented asparagus is another good GAPS Diet option.


Comments 37

  1. This is very helpful information. I am on full GAPS, but do not yet eat lentils, as they can really irritate my gut. I would love for you to add an image to the post, so I can pin! ๐Ÿ™‚

  2. Very interesting! I don’t really know anything about different types of starches, so thanks for the informational post.

  3. Thanks for this information, had never heard of RS before but we did make the waffles and have had NO gas. I think people probably have that happen when they eat the Bob’s potato starch. On to new knowledge and a new food, thanks to you!

  4. Hi, I want to introduce more RS in my diet. I have a couple of questions :
    1. I eat a lot of lentils, beans, chickpeas…is it better if a make them 1 day ahead and refrigerate? And And then just warm them up a little.
    2. Green plantains….i am from a part of Bolivia that eats lots of plantains. What about cooking green plantains like in the oven, cool and refrigerate them. Will it work as good as raw?
    3. Tapioca starch….is know is not the optimal, but since it is available here. Cook with it ( bake or thickening agent) or raw in a smoothie?

    Thanks!!!! ๐ŸŒธ

    1. Hi MJ,
      Thanks for your questions!
      1. Yes, making beans a day ahead is great. Some sources say that reheating a cooked and cooled bean actually increases the RS. As long as it’s been cooked and cooled once, it can be eaten cold or reheated.
      2. Green plantains, on the other hand, are a different kind of RS (2) that must stay raw and never be cooked. Once cooked most of the RS is lost.
      3. Tapioca belongs to the RS3 category; so it’s a good one to eat cold after it’s been cooked, or reheated after it’s cooled. ๐Ÿ™‚

      1. Thanks Megan!…what about tapioca starch? Is it OK to add it to smoothies? I read it has kind of a little bit less than potato starch but still a lot

        1. Sure, happy to help. ๐Ÿ™‚ If you heat/cook tapioca first and then add it to smoothies then, yes, it’s a good bet. ๐Ÿ™‚ Or, depending on the variety, it may already have been heated.

  5. I totally agree with the potato starch … I see that recommend all the time and think how is that good? Non organic potatoes – no thanks. I have really been enjoying incorporating healthy RS like cassava flour. Thanks for sharing this Megan! Always appreciate your knowledge.

  6. Hi Megan! Great post, very helpful, as I am in the initial stages of reintroducing RS now after being on GAPS. A couple questions for you:

    1. I have a known food sensitivity to tapioca (as do a lot of people it seems). I have read that cassava comes from a part of the same plant as tapioca. Do you have any idea if the nutritional profile of cassava is different enough to be safe to eat for those with a tapioca sensitivity? Or should I avoid it just like tapioca?
    2. Properly preparing/soaking grains and legumes involves fermenting them, right? For those with SIBO, fermented foods are contraindicated, at least according to most (but not all) experts. So I’d love to start including beans in my diet for RS purposes (and since my doctor has prescribed me to start eating more foods that promote the production of butyrate), but in order to properly prepare them I would need to ferment them, thereby making them not okay for me since I am still healing my SIBO. Am I thinking rightly about this?

    Thank you for your advice!

    1. Hi Allie, cassava doesn’t bother me; but tapioca does. But the nature of your sensitivity will certainly affect the answer. What reaction does tapioca cause in you?
      2. Great question. The fermenting that occurs with the predigesting is occurring outside your body so that it won’t happen inside your body! ๐Ÿ™‚ When foods are hard to digest they ferment in our guts. So by fermenting/preparing/soaking beans or grains, you are preventing or reducing the effect the food will have on your SIBO. When this is not true is with a living fermented food, and thus the confusion. Fermented foods like sauerkraut or yogurt are not cooked after fermentation or predigesting. The living probiotics exacerbate SIBO. Cooked foods that have been fermented are not fermented to create probiotics; they are fermented to break down anti-nutrients. So fermented foods like yogurt or kraut should not be eaten with SIBO. But fermented foods like beans and grains can be attempted. Even if they don’t digest well, it won’t be the SIBO being exacerbated by flora. This is the book by Norman Robillard Ph.D. that tells you which foods cause more or less fermentation in the gut, their fermentation potential:

      1. Hi Megan! My tapioca sensitivity came up in an IgG/IgA food sensitivity test I recently took; I don’t know what it actually does to my body since it’s been so long since I had it (likely in a processed gluten-free product that I ate prior to starting GAPS) and since I wasn’t in tune with my body enough at that point to realize it was bothering me. So with that in mind, do you think I should give cassava a try or not?

        Re: fermenting/predigesting foods, thank you for that wonderful explanation! So helpful!! I know that each food’s RS amount can change depending on if it’s been cooked or not, cooled, ripened or not, etc. Do beans and lentils have a high amount of RS after they’ve been predigested/fermented and then cooked? In general does predigestion/fermentation change the RS content of foods at all? Do you know of a source you could point me to that would have all this type of info in one place? Thanks again!

        1. I do not have much confidence in the IgG/IgA food sensitivity test; so yes, I think it’s worth a try to give cassava a try. ๐Ÿ™‚

          You’re welcome. Beans need to be cooked and then completely cooled to gain their RS3. They can then be reheated. To learn more specifics, my post on the topic was just published over at It should give you more guidelines about which foods are prebiotic and how RS foods should be eaten/prepared. ๐Ÿ™‚

          1. You have me so curious now about the IgG/IgA testing. Why do you not trust it? Is there something I should know before I spend any more $ on it?

            1. It is not very reliable. It changes based on what you have or haven’t eaten, as well as other factors. The elimination process and the food intolerance evaluation have been much for helpful to us.

      2. Another question: Sprouting a food (like lentils or seeds, for example) and then eating it raw would not exacerbate SIBO because it’s not a living fermented food, right? (even though it wasn’t cooked after soaking/sprouting as you talked about above). I’m thinking of the recipe you linked to that are for sprouted raw lentil slaw, for example.

  7. This is really interesting information. I’ve just started learning about RS and want to incorporate it in my families diet, but there’s a lot of contradictory information out there! I have a couple questions for you.
    1. How do sweet potatoes compare with white potatoes as a source of RS, and do they need to be cooked and cooled also?
    2. What about oatmeal? I’ve read raw oats are a good source, toasted oats are a good source, and also that you can cook oatmeal, refrigerate, and then eat it cooled. Which form would have the most RS and is it important to soak oats first as with other grains?
    3. Do you think green plantains are a better choice than green bananas and why?

    Thank you!

  8. I have read that once potato flours heated it no longer is a resistant starch. In fact the label on BOb’s pot. starch apparently says it is heated. So….wondering if cassava or tigernut flours are still a resistant starch after being heated? Love the idea of just getting green bananas from the store and making my own dehyrated powder.

    1. Post

      Hi Esther, thanks for your questions. There are different categories of RS. Potatoes belong to two categories: RS2 when raw and RS3 that needs to be cooked then cooled for the RS to form. RS3 foods may also be reheated after cooling. Cassava is in the RS3 category: RS3 and must be cooked and cooled for the RS to form. Some flours are heated enough in their dehydrating process to qualify, such as Otto’s. Tiger nuts belong to the RS1 group with nuts and seeds because the starch is bound within the fibrous cell walls. Green bananas are RS2 and must be eaten raw. The RS is lost when heated. Yes, lovely to make your own green banana flour! ๐Ÿ™‚ Just keep the heat low.

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