Update ~ RS2 and RS3 are Not Exactly the Same Thing

(Hat tip: M. McEwen) Feeding raw potato (RS2) in this ancestral diet study (human v. Theropithecus gelada) appeared to overfeed and increase the RS2-chomping gut populations—Bacteroides and E. rectale—in the human simulated gut. Populations that do not eat RS2 at all or proficiently—lactobacilli and bifidobacteria—were decreased with raw potato. These sub-colonies prefer dining on oligosaccharides (beans, inulin, endive, banana), RS3 and other fiber.

However, with simulated gelada baboon gut, minimal changes were observed and this is consistent with animals without salivary amylase. Only Old World primates known as ceropithecines have evolved AMY1 (salivary alpha-amylase) to consume starches from fruit seeds that they carry in their cheek pouches.

RS2 Alone Burns FAST&FURIOUSLY in Proximal Colon; But, No Change in Stool pH
RS2 is butyrogenic, (mildly) bifidogenic and burns with smoking hawwt intensity at the caecum. However, to flood the entire colon with health promoting butyrate, other plant fibers (including RS3) are needed to add bulk and carry the beneficial granules distally toward the rectum. In human RS2 alone trials, stool pH failed to improve compared with controls indicating that little fermentation occurred toward the end of the colon (here, here, here). One experiment was 4 weeks and low fiber. These experimental diets used RS2 alone + NSP ~10 g/day, similar to that typically observed in low fiber S.A.D., Paleo, VLC or Atkins induction diets (e.g. 1 fruit + 100 g/day vegetable + little legumes or whole grains). Conventional fiber is also known as NSP, non-starch polysaccharide.

Two cups of romaine lettuce is ~ 2 g NSP fiber; one 7.5 inch carrot, 2.3 g.

High stool pH indicates a lack of both colon fermentation and butyrate flooding the colon. More and more studies are showing that stool pH can be a reliable marker for colorectal cancer (Walker et al 1986; Newmark, Lupton 1990).

Granular RS2 particles are covered with a brilliant number of constellations for bacterial amylases to adhere and attack. On the other hand, crystalline RS3 matrices are gradually, slowly degraded with quite a lot of endearing and sustained fermentation to the distal colon, unlike granular RS2 starch (hat tip: Gemma).

“The starch granule size seemingly presents
a very favourable target for attack by
amylase with many potential sites for binding of the
enzyme. In spite of this apparent binding advantage, the
complete breakdown of starch within an intact granule is a
fairly slow process. Crystalline areas tend to be unfavourable
for enzyme attack and, in addition, the granules may
contain small but variable amounts of proteins and lipids
that can also hinder starch–amylase interaction. Most of
the starch consumed by humans will have been cooked
and/or subjected to various processes during food production
that disrupts the granules to a greater or lesser
extent, but raw starch is consumed in many animal feeds.
Processing that disrupts general granule integrity and
reduces the degree of crystallinity, increases the susceptibility
to amylase.”

We like RS a lot. It’s an unconventional fiber, and synergistic with other gut fuel. Together, they are bionic nourishment that our intestinal cohabitants are intimately familiar with for tens of millenia, if not hundreds.

While technically correct that raw potato starch is a valid form of RS2, using it as a sole source of RS for your gut microbes is probably not the best plan of action.  Looking back at studies that used just RS2, we see that RS2 is somewhat unique in that in ‘burns fiery hot’ once it exits the small intestines.  This means that the RS2 granules are converted to short chain fatty acids SCFA, mostly butyrate, in the cecum. SCFA and butyrate are mildly acidic and lower pH. In many ways RS2 ‘behaves’ physiologically and biologically like soluble fiber. Like pectin or gums, it does not bulk stools significantly compared with non-soluble fibers or retrograded RS3.

RS3 Burns Perfectly Prolonged All the Way to the Distal End of the Colon
Cooked-cooled, retrograded RS3 starch is a insoluble, large matrix of crystalline structures, and on the other hand, ‘burns slowly.’ It is insoluble and behaves like insoluble fiber and architecture to soft stools and providing bulk by increasing water holding capacity. I believe it provides a solid scaffolding for microbial ecosystems to colonize and flourish.

Ever notice how hardly anyone complains of flatulence when eating RS3 rich foods such as cooked and cooled potatoes and rice?  This is probably due to the fact that it is slowly fermented and the gasses produced are dealt with by gas-degrading microbes in a timely fashion. We had originally taken the lack of gas to indicate lack of performance, but this is wholly unfounded. The older ileostomy studies prove conclusively that the RS3, formed from cooked and cooled starches, arrives intact in the large intestine and modern microbe studies using 16s rRNA sampling prove that RS3 has profound effects on the gut microbiota leading to all of the positive changes we desire.

Epidemiological studies on consumption of RS3 rich foods like beans and lentils show protection against diabetes, obesity, prostate disease as well as colon cancer. In moderate fiber human studies (here, here), the combination of RS3, RS2, RS1 (total 38 g/day) + NSP 20 g/day (including raw green banana flour) was associated with significant improvements of every marker of gut health, including the largest drop in stool pH recorded in human studies. The lower and improved pH mark how microbiota fermentation and butyrate very likely and consistently flooded the entire length of the colon to the distal end. Also, dilution of ammonia and lower concentrations of fecal carcinogens (p-cresol, phenols) were noted. The authors concluded:

“In a typical Western diet (usually low in NSPs and starch) most
fermentation occurs in the proximal colon with limited effect
on the distal colonic environment (14)…

Fecal pH can be lowered by a variety of changes in the diet
(46, 47). Acid fecal pH has been linked with protection
against bowel cancer (48, 49). Epidemiological evidence
suggests that a drop in pH by 0.5 units is associated with
reduced risk (48, 49). During this study we were able to
reduce fecal pH by 0.6 units. To our knowledge, this is one
of the largest diet-induced changes in human fecal pH
reported. Studies using lactulose (SO) and oat bran have
recorded decreases of 0.4 units. The results obtained here
are most likely due to the higher amounts of [mixed] RS used
because there was a significant inverse correlation between
RS intake and pH, and between fecal starch and pH.
In humans the majority of colon tumors occur in the distal
colon (51). Thus, the measurement of fermentation-dependent
events in feces may reflect the environment in the distal
colon (52), and provide useful predictors of the antineoplastic
properties of certain diets.”

The mix of cooked RS3 and fiber produced outcomes that vastly contrast with the human study where RS2 did not dilute ammonia, but retrograded RS3 did.

Therefore, we feel it prudent to not seek total intake of prebiotic, fermentable fiber from isolated RS2 sources.  A diet supplying very little fiber, regardless of total carb count, and supplemented only with a refined RS2 (such as Bob’s Red Mill potato starch or Hi-Maize corn starch) will not be nearly as healthful as it could be if the RS2 was augmented with an array of other fibers. 

Both insoluble fiber and RS3 are enriched in low GI starchy foods — lentils, peas, legumes, whole GF grains. Other roots/vegs and tubers are also abundant in either RS3 (sago, cassava, taro, heirloom potatoes) or insoluble fuel (turnips, okra).

RS and Total Dietary Fiber
From the ancestral evidence and modern studies, just getting the USDA recommended 25g/day of fiber is not enough.  More likely 40-80g/day would be optimal.  “Fiber” is such a fickle word…the fiber listed on nutrition labels is considered Total Dietary Fiber which includes every type of fiber that resists digestion.  Googling for the information you can get ‘conventional fiber’ charts.

From experience, 20-30g of ‘USDA-approved’ fiber is not that hard to achieve, nor is 20-40g of RS from real foods. For example, these 3 meals provide a nice blend of RS and fiber:
  • ½ cup soaked buckwheat porridge, ham, 1 Tbs raw potato starch BRM or green banana flour (WeDo’s or Mt. Uncle’s)
  • 1 cup cooked broccoli, 1 cup of pre-cooked lentils, ¼ cup kraut, ½ cup walnuts
  • chicken kale salad with raw carrots and 1/2 cup wild rice, five (small) roasted red potatoes

If you are concerned about the effect on blood glucoses (BG) and the glycemic load on the above foods, be assured that all the above have low GIs (glycemic indices) of ~20-50. Each meal contains 1 to 2 servings of carbs (15 net carbs) and need to be adjusted and personalized based on individual insulin sensitivity, exercise, diet, relaxation, stress, sleep, hormone status and health goals. PHD is 150 g/day high GI ‘white’ carbs, in other words, ~10 servings carbs.

Fermenting (soaking) lentils and legumes completely changes the structure of the beans and unlocks many nutrients, cooking then enriches insoluble fiber in addition to creating more resistant starch—besides making them edible. Cooling them crystallizes further resistant starch. Expanding on raw and cooked tubers and root vegetables, consuming a diverse and variety of plant fiber (green banana/plantains, lentils, legumes, gluten-free grains, nuts) secures phytochemicals which are anti-aging and cancer-protective antioxidants.

3 Posts Written By: Tim Steele, Grace Liu

NSP = non-starch polysaccharide (conventional fiber)
RS = resistant starch
RS2 = raw RS
RS3 = cooked/crystallized/cooled RS (superfood = fuel for superhumans + super gut flora)

See prior Animal pharm:

Feeding the Microbiota: Non-Starch Polysaccharides (NSP), Resistant Starch (RS) and Mucous

  • Anonymous

    Great info. The one thing I am unsure of is based on Chris Kresser’s book in which he says, from my memory, that the soaking of legumes does not effectively remove the anti-nutrients. Please could Grace and Tim you give your views on his assessment.

  • Anonymous

    Back Again. Just went over and read CK’s http://chriskresser.com/the-truth-about-legumes-saturated-fats-and-vegetarian-diets and he is actually saying that it’s the fact that they are not that nutrient dense that he recommends that people don’t eat much of them instead of more nutrient dense protein sources, and that soaking and cooking does get rid of the lectins. But your saying that they are nutrient dense for our bionome buddies. Is that correct?

  • G

    Tim ~Thx, was a pleasure!


    Thx — YES. Love ur phase — Biome buddies!!

    Chinese, Japanese and Okinawan all consume a lot of mung, red, and Adzuki beans as well as mung bean sprouts and cellophane sheets and noodles. These foods are ancestral and a bedrock for brains and nutrition for a reason.

    The thing about ‘nutrient dense’ ignores the gut microbiota. Look at this study. All the conventional fiber was found upon excretion. So almost no ‘fiber’ was fermented by the gut microbies yet the DAPA (microbial biomass marker) was extremely high for the high RS and high fiber foods — amaranth and cassava.

    Cellulose, lignin and hemi-celluloses are not readily degraded but some are and additionally they provide the physical scaffolding/architecture for all the rest of the gut biomass to do their work.

    Nutrient dense for the microbes are not considered until now because we have the optics to actually peer in — 16S rRNA pyrosequencing and GDX functional medicine stool testing.


    J Pediatr Gastroenterol Nutr. 1991 Jul;13(1):59-66.

    Effect of dietary fiber and starch on fecal composition in preschool children consuming maize, amaranth, or cassava flours.
    Hamaker BR1, et al

    Metabolic balance studies were carried out in young children fed diets based on maize, amaranth, or cassava flours and in corresponding casein controls. Dietary fiber intakes were 22.2, 20.5, and 9.0 g/day for the maize, amaranth, and cassava groups, respectively. Fecal energy losses at least doubled in all test diets when compared with the corresponding controls and could generally be accounted for by recovered fiber in the feces. Fecal starch was also a significant contributor to fecal energy in the cassava group. All cassava fiber was recovered in the feces, whereas only 48.4 and 16.3% were recovered from ingested maize and amaranth. 2,6-Diaminopimelic acid (DAPA), an indicator of bacterial mass, was highest in the cassava group. Expired breath hydrogen was highest for those consuming maize or cassava. Resistant starch may have been responsible for the high DAPA and breath hydrogen values in the cassava group.

    (BTW cassava is chock full of cyanide and can cause irreversible neuropathy in low protein, low B vit diets — they take extensive food processing, more other foods but in the tropics it’s one of the ancient lifelines)

  • Anonymous

    Thanks for all your work and useful information over the past year or so. Can’t even begin to imagine the amount of hours you must have put in researching this subject.

    A couple of questions: 1)do you still recommend or practice a potato fast.
    2) how long should lentils be soaked, I’ve seen everything from never to a full day.

  • Fantastic stuff. Do you happen to know any way of figuring out RS3 content other than an expensive assay of food? Our startup is making an oat based bar. Logically, we should have some RS3 since raw oats are quite high in RS2, but we can’t be sure.

  • Thanks for the quick response. I managed to get past the paywall on “Resistant Starch: A review of analytical protocols for determining resistant starch and factors affecting the resistant starch content of foods” which corroborates the methodological difficulties with doing an assay. Identical materials do not result in identical assay results when slightly different techniques are used. The section on processing methods indicates to me that we should be using a moisture-heat method on our oat flour before cooking. Allowing the flour to be moist for 24h before cooking increased RS content by 50-100% in several samples. That, combined with the fact that we are asking customers to refridgerate once it gets to them should result in a decent amount of retrograde formation.

    We can at least look at downstream effects. Are people seeing improved BG control? We are running our beta testers through some metrics and blood panels to see what is going on.

    Again, thanks for the help. Keep diving into this stuff, human health is at stake and no one else is gonna do it for us.

  • Intrigued

    Question. Green plantains and green bananas are a good source of RS2. When cooked/cooled are these good sources of RS3?

  • Great article.

    To anonymous, my most recent thinking on legumes is here: http://chriskresser.com/are-legumes-paleo

    I think they’re a great addition to the diet as long as you tolerate them well. As you pointed out, we need to consider not only feeding ourselves, but our gut bacteria.

  • Anonymous

    Tim – regarding things that have been baked, then cooled……

    I make a bread from almond meal and a host of other stuff from the pantry. If I add potato starch to that mix, bake the bread and then refrigerate it (which I already do) will the potato starch return to resistant starch?

    Thanks for all you do!

  • Anonymous

    I have asked this on another post but didn’t get a response, I think this post is a good place for this question-
    If potato flour (not starch) has no RS , what is different about the processing of green bananas to make banana flour which preserves (or perhaps forms) RS? In banana flour,is it granular RS2 or crystalline RS3? I think the raw green banana is RS2.

  • I recall that roasted and cooled potatoes have among the highest RS in the cooked category from the “RS content of foods” list. I thought I also read that it is partly the removal of moisture that helps increase this. Doesn’t this argue for cooking methods like shredded potatoes (e.g. hash browns) with a lot of surface area that during roasting would remove a lot of moisture. Thus, after cooking and cooling would be even lower moisture and presumably higher RS? Cooked, cooled and gently reheated hash browns? Would the addition of oil mess things up?

  • Anonymous

    I think I found the answer to my question – as well as a great research article about making pasta out of banana flour The flour is made by desiccating the green banana and then grinding it into a flour, it is at no time cooked.
    Here’s the link -http://www.researchgate.net/publication/222301668_Unripe_banana_flour_as_an_ingredient_to_increase_the_undigestible_carbohydrates_of_pasta/file/9fcfd504e24897ac30.pdf

  • Wilbur

    I’ve cooked a lot of beans forever. I have a pound cooking right now. I never soak. Many of the cultures I am aware of in which beans are an important part of their diet do not soak. Rick Bayless prepares thousands of pounds per year and doesn’t soak. Neither here nor there, I guess.

    But when I looked at the links you provided (thank you, very valuable) I read the emphasis to be on fermenting. I prepare some fermented bean recipes, one in particular is black-eyed peas, and know from that that a fermented bean seems quite different from a soaked bean. It is sour, for one, as you’d expect. I don’t have time to fully digest these studies now, but I wonder if an overnight soak (what is usually recommended for soaking beans) imparts significant benefits.

    I know there are lots of cultures that use truly fermented beans, but for me “soaking” is something elseeven if beans soaked for days give fermented beans.

  • Wilbur

    I’m not sure that links to the study you mentioned, but maybe I am missing something. Nonetheless, I am running my own search of “plantarum legumes fermentation” on pubmed and am finding some incredible stuff. After years of arguing against soaking beans, I might have to change my mind. Excuse me, fermenting them…

    Thank you yet again.

  • Anonymous

    If you boil the beans for 10 minutes after the overnight soak, don’t you kill all of the L. plantarum?
    If you are looking for a fermented product with this bacteria, it can be found in Bubbie’s brand dill pickles.

  • G


    Raw oats are great for RS2, beta glucan and other fiber however the phytates cause zinc and iron deficiencies when consumed on a regular basis. Actually Quaker funded these studies!


    On the other hand, healthy gut health and probiotics counter phytate problems by increase mineral absorption and assisting zinc, iron and other mineral update in the gut. So, raw oats might be doubled edged — for those with sick guts, it may further compromise. For the gut-healthy, no problems as long as everything is balanced and no deficiencies (probiotics, fiber, B vitamins, etc).

  • G

    Chris Kresser,

    Thank u dude! Yes whole (gluten free) grains, maize, lentils and legumes were are probably paleo and eating with decent food processing prior to the neolithic, I surmise (haven’t looked hard). Appreciate the link.

    When humans skimp on food processing, that’s where the lectins, phytates and anti-nutrients start to become problematic. Cooking made our brains big. No doubt. Fermentation made everything better. In native Africa, I’m shocked how many foods and grains/maize are fermented (without refridgeration). Reminds me of my grand parents. They ate only fresh, raw or fermented foods and beverages.

    Fiber also made the brain faster and fat-dependent: acetate, propionate, butyrate.


  • Martin Archer

    I guess a bean dip would be a good way to eat cooked and cooled beans without re-warming them.

    Any suggestions for synergistically beneficial foods to combine this with?

  • G


    Tim really answered your questions! Watkins from Mt Uncle’s Banana farm on his website as well in person he has tested baked GBF (green banana flour). He has found about 25% retention of RS.

    Naturally this is RS3, retrograded. Many factors affect this and may increase this from what I’ve seen in rice or potato studies — dry heat, heat, high heat, less salt, pH, cold storage, freezing/staling effects, etc. I can’t tell you what maximizes yet for.

    Mt Uncle’s has ~ 40-50% (RS2)
    WeDo’s 17-20% (RS??)

    but they actually boil the bananas prior to removing the skin. It is actually most likely RS3 which isn’t bad as this post can help clarify the differences.

  • G


    The benefits for fermentation in food processing is what many modern folks are missing out on! Prior to refrigeration, chemical preservatives, nitrates, etc, food was either fresh/raw, cooked or preserved naturally with microbes. They were our refrigerators!

    This is one of most eye opening thesis projects I’ve ever read (versus ‘snore’)


    Also in native Africa, the cradle of humankind and human super-guts… everything is fermented — oats, grains, porridges, dough, chutneys, fish, fufu, cassava, legumes, vegetables, milk, ‘microbrewed’ beer, grain alcohols, etc


    Ch 1

    Ch 2

  • G
  • G

    Tim~ your smashed retrograded pinto beans sounds AWESOME~!!! I’d even add some homemade tomato chunks or finely diced green onions, like a 7-layer dip but mashed together, with drizzled caesar dressing. We use caesar dressing as pizza sauce, because it tastes like cheese! Plus it’s got omega-3 from anchovies

  • Wilbur


    Thanks to the links to the thesis. I will definitely enjoy reading it in more detail when I can.

    I too believe in fermented foods. I eat kimchi and raw miso everyday. The kimchi is made with miniature leeks or scallions, veryy fibrous. The miso is made with dandelion greens and leeks.

    My issue, if one calls it that, is whether a short soak accomplishes anything. I’ve done fermenting, lots of it actually, and studied it. My intuition from it is that beans would take much longer to be significantly modified, to use the words in the thesis. In the things I am reading – granted quickly because I’m busy – I’m seeing 48 to 72 hours, even in the thesis. That’s how long I ferment beans for an African dish I make. They are wonderfully sour and not at all like a bean soaked for 12-24 hours.

    In any case, you both have convinced me to soak my beans at least for a couple of days!

  • Anonymous

    Hi Tim,
    Referring back to Lp and kefir grains comment…
    I make kefir daily from what I believe to be Dom’s grains, given to me third hand – Do you know what strains purportedly live on those grains, and is there a way to conventionally test my grains?
    Thanks again, you are a treasure trove of information!!!!!

  • Anonymous


    Sounds like you don’t eat your miso as soup, since you say it is raw. How do you eat it? I love the South River products too!


  • Wilbur

    Ellen –

    I just spoon out a teaspoon or so and eat it. It’s part of my supplement regimen. It used to be hard to do, but I now look forward to it.

    I am really fond of their dandelion leek and their red pepper garlic. I like that their salt level is not as high as other brands. Their tamari is also very nice in case you have not tried it.

  • Anonymous

    So if I mix two tables spoons on potato starch with hot water then leave it in the fridge to cool overnight, do I have an RS3 supplement?

  • Anonymous

    The ‘original LP’ says… here is a link to show you all the strains in kefir. (And, Tim, I don’t have funerals for them… because I’ve never killed one!)

  • Nixtamalizing field corn (cooking it in a base solution like lime water) so it can be wet ground as the ancient mezoamericans did actually makes niacin bio available and releases other good protiens. The problem with corn having poor nutritive value is that it is rarely nixtamalized and usually just ground. Even most corn tortillas for sale in supermarkets are not made with truly nixtamalized masa. There is an industrial enzymatic process that is used that does not confer the same flavors or nutritional gain. I bet there is plenty do resistant starch in nixtamalized masa. Whole civilizations ran on it…

  • Hey Wilbur,

    That’s amazing — all those dandelions, other inulin rich veggies, raw miso, kim chee and sour beans.

    Tim has said that his beans starting smelling up the house during the ferments, so I didn’t worry about toxifying my family when I accidentally leave out my beans for a few days because I don’t have time to watch them cook and bubble for a few hours (I don’t have a slow cooker here in China).

    Many of the African fermented porridges and mashes are ‘sour’, and the locust bean and oil bean condiments are ‘proteolytic’ in smell (eg rank LOL). Where fat and protein ferment, I think the unami flavor that is imparted is something ancestral and savage that we all crave and blindly pine after. They must be coordinated by our healthy gut microbes attempting to re-poopulate themselves, ahaha.

    Look at this study. The microbio studies of the ‘blooms’ that occur with native African foods — various staples — which are ALL fermented. L plantarum doesn’t make a significant appearance until 48hrs. The others all fill in by 72hrs.

    Occurrence and antimicrobial properties of lactic acid
    bacteria during the fermentation of cassava mash,
    maize and sorghum grains

    There really is no need for SBO probiotics in places that still consume native fermented foods. Every bite is 10 MILLION MICROBES PER GRAM. It’s teeming with life, enzymes, and vitamins. One-quarter cup is 120g x 10 M cfa = 1.2 trillion microbes. ~1% of the gut microbiota. No wonder native Africans never get polyps or colorectal cancer.

    For fecal transplants, 1/4 to 1/2 cup poop is used. Half of this is the biomass of alive and dead bacteria. We would not need to resort to these (life-saving) ‘procedures’ if we merely reverted back to a slight semblance of ancestral and artisanal living and farming…

    Isolates in fermenting substrates 0 h 24 h 48 h 72 h 96 h

    Cassava mash ‘fufu’
    Leuconostoc lactis + + + + +
    Lactobacillus plantarum – – + + +
    Lactobacillus fermentum – – + + +
    Leuconostoc carnosum – – – + +

    Maize grain ‘white ogi’
    Lactobacillus fermentum + + + + +
    Leuconostoc mesenterioides – – + + +
    Lactobacillus bulgaricus – – + + +

    Sorghum grain ‘red ogi’
    Lactobacillus casei – + + + +
    Pediocouccus acidilactci – + + + +
    Lactobacillus plantarum – – + + +
    Lactobacillus lactis – – + + +
    Lactobacillus brevis – – + + +
    Lactobacillus delbrueckii – – – + +


  • Alex~

    Thanks for your point. nixtamalizing field corn is an ancient practice like many other millions that are going to the wayside to our detriment and those of our gut (not to mention the horrific effects of Bt enterotoxin to our guts and lateral transfer of these DNA that transform the gut into Bt factories).

    Native Africans consume ‘stale maize porridge’. They boil then inoculate and allow to cool, ferment for several days. The cooling increases RS but the microbes change/improve the nutrition. Do you think it is similar in regards to nixtamalizing of South American corn?

  • Thx Lauren and Anon – -I was wondering the same thing for a while!!

    I wonder too if it depends on organisms in the air, utensils, water?

  • Man, doesn’t kefir sound like fermented horchata?

    Even the pictures look like starch granules being invaded by gut microbes.

    Nigerian tiger nut milk is called kunnu aya. Kunnu is any milk made out of nuts, millet, sorghum, rice, peanuts, tiger nuts. (nice pictures of African marketplace)


    In Venezuela they ferment horchata to alcohol. “Horchata spread across the world with the Spanish colonization of the Americas. Each country developed its own version of the drink, and today there are many different kinds of Horchata. It is especially popular in Latin America, where there is a high rate of lactose intolerance, due to its milk-like taste and look. In El Salvador, it is made with ground morro seed from Calabash tree gourds instead of tigernuts. It is strained afterwards for a smooth, silky texture. In Nicaragua and Honduras, the jicaro seed replaces the tigernut. The Venezuelan version of horchata is sometimes called chicha, and is often fermented into an alcoholic drink. “

    But it appears tiger nuts are only fermented as a new food processing step to increase nutrients.

    Adejuyitan, J.A., et al, 2009. Some physicochemical properties of flour obtained from fermentation of tigernut (Cyperus esculentus) sourced from a market in Ogbomoso, Nigeria. Afr. J. Food Sci., 3: 51-55.

  • Nixtamalization is pretty much straight chemistry as a pretty long boil is involved. That said, it seems inevitable that masa got innocolated and fermented but that step was lost at some point after we got germ phobic. Been fooling with wild fermented kraut and kimchee after reading Katz’ book. Will try with my next batch of masa. Btw your comment re gmo corn was the first time I finally grokked what could be the real danger. That being the production of “weed killer” bugs which might harm the good bugs in our gut.

  • Also, I know I’m kinda late to the party here, but am I crazy for thinking fluorinated/chlorinated/treated water is part of the problem? I know you can’t ferment with it. So it can’t be good inside you. What is it doing to everyone’s guts and biome?

  • Anonymous

    Where I live, I can buy fresh beans (mainly pinto) straight from the pod. I can put them straight into a pot of water and they get super soft after 30 to 60 minutes. But should these fresh beans also be soaked and fermented to reduce toxicity and/or maximize nutrition content?

  • Wilbur

    Dr B G –

    Thanks for the link to the study. If I read it correctly, it confirms my intuition. The only thing I know that ferments in 24 hours is corn, probably because of its high sugar content. But I am merely a tinkerer.

    I like taking things to the extreme. When the family is out of town, I like to do things I can’t otherwise do. Like run up my fiber content to extreme levels. Today has been extraordinary, and no ill effects. I’m such a bad boy…

  • Anon~ I have no idea! I eat fresh long beans and chinese broad beans… hope they are fine!

    Alex~ “fluorinated/chlorinated/treated water” Yes I’d expect them to lower fermentation but maybe at some critical threshold then the fermentation will bloom, albeit delayed? We’ve never fermented until this past summer but we have reverse osmosis water in China, so no problems or notable delays. Tim uses well water, so again no chemicals or halides to slow fermentation.

    You bring up an excellent point. Every factor that affects the gut adds up and accumulates. What we put into our mouths is the main driver — oral tolerance — when the gut is permeability we actually ‘vaccinate’ ourselves and bring out hypersensitivity to normal environmental exposures — small amounts of gluten, casein, dander, pollen, etc. So I believe fluoride and chlorine aren’t great but added together, it’s not something to dismiss.

    Added to are really affecting us as a species imho:
    –C sections
    –antibiotics because these go in via the mouth and gut
    –vaccinations (mercury and aluminum containing ones)
    –contaminated water (Keith can expand — protozoa, parasites, arsenic, mercury, urine and fecally excreted pharmaceuticals, etc)

  • Wilbur~! UR SUCH A PUNK, a gut punk! lol

    Alex~ Artisanally prepared masa and corn sound great. I didn’t know about the fermentation step which makes clear sense!

    Read this — you’ll be freaked out like me

    Fetuses and moms had detectable Bt and glyphosate (round up) in their blood.

    Many scientists suspect that it’s not just dietary intake but transformation of the human gut microbiota. Art Ayers is quite profound — the gut bugs share all sorts of DNA bits, plasmids, viruses. Nothing is off-hands.

    In fact from retroviruses mammals evolved our traits
    –concealed conception
    –placental births (internal egg ripening)
    –AMY1 amylase in the saliva


    This author Villarreal wrote “Such acquisitions of complexity have
    always been difficult to explain by a simple Darwinian process. These
    dilemmas include the origin of the eukaryotic nucleus, the origin of
    flowering plants, the origin of the adaptive immune system in animals,
    and the origin of live birth (viviparous) placental mammals.”

  • Mike Ede

    If some of you smart cookies wouldn’t mind looking at this paper and letting me know what you think:


    Basically 3 days of carb loading using raw potato starch saw a large increase in muscle glycogen. If the bulk of PS is fermented into SCFA then how on earth did the PS get converted to glycogen? Personally I am going to run with it anyway (high PS for 3 days) as I have a 10 hour endurance ride on Sunday and need all the help I can get.

  • Mike Ede

    Thanks for your thoughts Tim, it was a three day protocol with no more than 50g of rs an hour. Presumably in those three days RS loving bacteria numbers will have gone through the roof. I found it more amazing that so many tolerated it well! Given that I am shifting from low carb / fasting onto this carb loading protocol (which will see consume about 7 or 8g of carbs per kilo + the PS) I can’t see insane levels of PS hurting and relative to my typical carb consumption it will be a huge increase.

    Glad it gave you a chuckle, thanks again for taking a look.

  • CS

    I hope someone can help me clarify some things about beans.

    1. Is it correct to say that uncooked beans contain RS1?

    2. If so, do they lose their resistant property when cooked?

    3. When cooked and cooled, do they become RS2?

    4. If so, will they still become RS2 if cooled in water? (I’m asking this because I normally cook them by boiling)

    Thanks to anyone who can provide answers to the above.

  • CS

    Thanks for the answers, Tim.

    There is a fifth question that I should have asked: Will cooked-cooled starch lose RS3 if reheated in water?

    You did say that “it’s all about driving the water out of the starch”. But while you guys mention that dry heating increases RS3, I couldn’t find anything that says that wet heating decreases RS3. (I may have read it somewhere but can no longer find the source).

    Thanks again for your answers.

  • CS

    Thanks again, Tim.

  • Mike Ede

    Well I attempted the carb loading protocol from the paper above, consumed 500g of PS in 50g doses hourly. No problems at all, minimal wind. Then ate some fruit cake late in the evening and all hell broke loose! Some 14 hours after my first dose of PS I started to generate significant volumes of wind which carried on for 36 hours after the last dose was taken. Also awoke early on day 2 for the worlds biggest dump, not pleasant. I am used to taking PS regularly with Prescript Assist and Primal Defense yet it had this effect on me, how the hell could people do three days at this volume if they weren’t used to it. Other than the wind and big dump can’t really report any good or bad findings although I wasn’t hungry on day 2 (which was a pain as I was carb loading for my bike ride on day 4, which went very well)
    Doubt I will try this exact protocol again (as I failed to complete it) but will certainly look at much higher levels of PS in the run up to long cycle events.

  • Laney

    Tim, Grace,

    Re bean preparation, what do you think (or know) about using the dried Japanese seaweed kombu as part of the soaking and cooking process?

    It is said to significantly counteract the “gas effect” and is generally stated to make them more “digestible”, whatever that means – but I can’t tell whether this is because it actively reduces the RS content or some other process that is synergistic from the RS perspective. Any pointers?

  • Anonymous

    Hi Grace

    I have a quick question. I understand that cooled cooked potatoes have R3. So if you reheat the cooked potatoes, do you lose the R3 until the reheated potatoes cool again or the does the R3 survive the reheating?


  • Steve

    You lose about ~25%

    However I think there are several factors that might affect this
    –al dente cooking preserves more RS3
    –roasting crystallizes more RS3 by sometimes double (20 g v 10 g for a 100 g potato)
    –how long and cold the potato is stored before reheating

    Englyst 1987 AJCN
    Pmid 3812341

  • Thanks Grace.


  • Mycroft Jones

    Hi Dr. B G. I see you almost answered my question in an earlier post. Can you answer it?

    So, cook the potatoes “al dente”.

    Then cool them… for how long? What is the sweet spot for cooling time and staying cool time?

    When you say roasting can double the amount of RS3, does it matter how long you roast, or is it just “roast til warm, then pull out of the oven?

  • Mycroft Jones

    Thank you Tim! Any thoughts on using roasted chicory as a way to get a good dose of inulin along with all the polysaccharides you mentioned over on Richard’s blog? The warning for pregnant women to avoid it makes me a little cautious.

  • Anonymous

    Chicory root can be roasted and used as a coffee substitute. I’ve never heard of anyone eating raw chicory root, but the leaves are called Belgian endive, or witloof. The leaves are also high in inulin.

    I don’t believe that the beverage made by brewing roasted chicory root contains much inulin. Inulin is subject to degradation from heat. Still, I believe it is a healthful beverage and a good coffee substitute.

    Chicory root is grown mainly for processing into inulin and FOS, for use as a sugar substitute. Most inulin you see in supplement form comes from chicory roots.

    Apparently the plant family that chicory belongs to (along with ragweed, chrysanthemums, daisies or marigolds) are troublesome to many people much like some are sensitive to nightshades. Pregnant women are warned against chicory root, but I’ve never seen that warning applied to chicory derived inulin.

  • I am on Wahls Paleo+, combined with AIP, LCHF/ketosis. How do I implement the RS3?
    I take 2 tsp gelatinized maca, is that a valid RS3 source?

  • Like all new diets/introductions, it’s always prudent to go low and slow. Maca has no RS that I am aware but like other tubers (kudzu, konjac) many other fiber components exist and amp up gut metabolism and health.

    Please see #2 and implement the 7 steps eventually

    Good to hear again from u!

  • thank for your answer!
    I am very weak at the moment, it is hot here – 25-30 C
    I had a bad experiment with raw maca… FODMAPs problem flared… Anyhow am now titrating mag citrate to the right dose.
    Am now full on wahls paleo plus, restricted with some AIP.
    How do you see RS3 combined with th Wahls paleo plus?
    Oh BTW I quit the psyllium husk and now take kombucha every night with PS, TS, GBP and grassfed collagen hydrolysate wit a PA aand a lactoferrin capsule. It seems to optimize my stools.

    Would cooking and cooling potato starch in something like a pancake (with a green plantain) be a solution maybe? I can freeze them to maximize the effect and eat one each day to make the effect even…

  • Step #2 is a problem on th Wahls protocol…
    I do PS and TS and do approx. 1 cup berries a day.
    Dont respond very well to the starches…

  • S3=RS3!

  • Balla,

    Black plantains don’t have as much RS2 as green. Konjac and Kuzu are wonderful and have been used for medicinal purposes for centuries in Asia but they have no RS yet feed the gut very well.

  • So cooled plantain flour cookies would be a good plan? I make my own from raw green plantains on the dehydrator.
    And what about cookies with a combi of GBF and BRM PS?
    Adding some kuzu and konjac every now and then might be a good addition.
    How do you see RS3 combined with the Wahls paleo plus protocol?

  • Doggerms

    I have been epically strict low carb for 2 years and started getting bad problems with dry eyes,infections, cold hands, and fasting blood sugars in the 120’s. I started adding the bionic smoothies plan B a couple of months ago and had daily fasting sugars in the low 90’s post meal sugars avg 115 and feel warm and great. Thank you and Dr. BG and your blogs for helping me.

    I have tried to add RS3 black beans to my diet but they are increasing my glucose levels too high both fasting and postprandial. Is RS3 so important that I need to continue self testing for an acceptable source?

  • Doggerms,

    You’re so welcome. I love hearing resolution of health problems like yours.

    How is your thyroid/adrenals? Exercise (cardio, lifting)? SBO probiotics? Vitamin D/sunshine? Omega-3? Zinc/mag? All these factors impact carb tolerance and insulin sensitivity

    RS3 is important and ancestral but the caveat is that they have carbs. OTOH RS3 will help carb tolerance!

    Have you considered eating room temp heirloom roasted potatoes or room temp beans or lentils that have been stored in fridge one day? These are low carb sources of high RS3. Don’t need a lot. 1/2cup 15-20 g of super bionic RS3.

    If you take along with bionic fiber (both version A+B) can have better carb tolerance over time.

    Have you tried 1/2 tsp glucomannan with 2 cups water for fat loss and improvement blood sugars?

    How has your A1c improved since bionic fiber over your experimentation time?


  • Doggerms

    Dr. B.G.

    Thanks again for the great knowledge I am experimenting with all of your suggestions.

    I have been checking my blood sugar 3 times a day for years and I was able to determine within a day that the knowledge that you are transferring is effective and helpful for me based on direct observation with repeatable results for about 50 days so far.

    I forgot to mention that I had developed a severe sciatica during my low carb experiment and after many visits to doctors have been taking NSAIDS for over a year in order to sleep. I probably really stressed my microbiome because after I started to feed the bugs my sciatica has almost completely resolved.

  • Doggerms

    Which probiotics have you tried? Probiotics (naturally) are shown to relieve pain in trials and several anecdotes.

    “after I started to feed the bugs my sciatica has almost completely resolved”

    Love LUV LURRRRVVV hearing this!!

    Have you tried version B of my super bionic fiber combo? It has INULIN. It is a fat-burning fuel for the gut and us! I’ll write more later but I discussed briefly on the RUGBY POST

    I’ve been adding Heather’s organic acacia fiber (hat tip Keith and Duckie) to Version B and can’t keep body weight or body fat on (unless I eat sugar/desserts). Give it a whirl and report back please?


  • Doggerms

    Dr. B G

    I will try and report back after a few months.
    Im not a medical professional just a person with a broken metabolism and a glucose meter. I did get some great results with PS, Psyllium, Amazing Grass and a Bubbies Dill Pickle or Kraut in amounts titrated to my blood sugar readings. I did add SBO’s later but my major improvements came before adding them.
    Im going to try and follow your advice and get my regular physician to work with a functional medicine expert for monitoring and testing to let some wise people help keep an eye on my health with an increased focus on gut health.
    Your help in leveraging the giftedness of the many medical leaders, researchers, thinkers, etc. and making it widely available is deeply appreciated.

  • Doggerms,

    Yes let’s increase conversations about the gut and metabolism all together. UR VERY WELCOME 😉

    Your fermented foods are fantastic and abundant in L plantarum, a widely studied microbe with many anti-inflammatory properties including pain relief. Mood/mind/addictions/metabolism all go hand in hand, no? (been there) it’s the gut also and micronutrient and hormonal deficiencies. Please have these addressed otherwise the gut cannot get better in the long run. Eating foods rich in phytonutrients, polyphenols, antioxidants, vitamins, minerals +soil from healthy farms is vital. Don’t ignore.


    I love Bauman and their nutri program. Search ‘insulin’ and you’ll get more fantastic strategies to fix metabolism.

    Unfortunately the document overlooks gut health. Because the ‘limbs’ of our gut microbiota are gone/amputated/lobotomized, we are lacking the organisms that metabolize for us. There is no optimal probiotic (yet) that can mimic the ancestral exposures from farms, healthy animals and healthy dirt.

    Do you have any farms near you? organic, sustainable and biodynamic?

    How many puppies do you have? I wonder if they have delivered some nice parasites and pathogens to u! My foster kittens might have (or a salad in California or Shanghai). If the gut is compromised, vulnerability to pathogens is higher, unfortunately.

  • hi
    where can i find a guide to what amount of RS foods have in raw and in RS3 cooked and chilled ?

  • aj1441

    Hey I don’t have one but pubmed has all the studies. There is some variability based on plant species, heirloom v non-heirloom, type of bean/potato/rice, etc.

    Let me know if you find a handy chart!!

  • aj1441,

    I forgot here is a short list we compiled with inulin/OS v. RS2 (raw) and RS3 (cooked)

  • Profound stuff. Seems important to acknowledge the mechanism for RS3 lowering ammonia in the colon (associated with cancer and epilepsy), microbes such as bifidobacteria:

    Here’s more regarding the mechanical differences in RS2 vs. RS3 where RS3 makes it to the colon instead of feeding overgrowth in the small intestine, lowering workload for kidneys and liver:

  • Stuart Mather

    Dr B.G.
    I understand why RS3 beats RS2 every time,but I’m wondering why you are so fond of inulin? It ferments fast and hot in the proximal colon, doesn’t reduce fecal pH and often causes as pronounced,if not worse flatulence and/or bloating as RS2. Granted it does feed the ancestral core, which RS2 doesn’t, but so do a lot of other fibers too, such as RS3.
    So why do you promote inulin so enthusiastically?
    Btw have you heard of a type of legume called the ‘lupin’? Negligible starch or sugar (so useless for RS3) but about 40% fermentable fiber and very low in phytates lectins and trypsin inhibitors. So presumably they’d be great raw (soaked meal). Also they exert a powerful stool pH lowering effect. They are better known as stockfeed, but gaining increasing popularity as
    a functional addition to the human diet. I noticed a report years ago of a study showing that they had a very pronounced effect on male sheep libido. Haven’t noticed anything yet, but it’s only been 3 days. I’ve just been adding a couple of spoons of raw lupin flour to my daily bionic fiber smoothie.

  • Anonymous

    Hi – I am fighting candida with S Boulardi and a low carb, low sugar diet. May I ask your advice as I am thinking of changing a few things based on your blog but want to retain the S Boulardi if I can
    1. Will Prescriptions Assist counteract the S Boulardi as it is a yeast
    2. Will digestive enzymes counteract the S Boulardi?
    3. Will the addition of cooked and cooled rice and cooked/cooled fermented beans feed the Candida or is it safe to proceed
    4. Does barley grass have a therapeutic place in this regime

    Many thanks, Nick

  • Anonymous

    I found a banana flour made from Musa acuminata:


    Is this good source of RS3?

    Characterization of resistant starch type III from banana (Musa acuminata):


  • Nick,

    Will the addition of cooked and cooled rice and cooked/cooled fermented beans feed the Candida or is it safe to proceed

    Yes — so weeding helps — ck out the Gut Guardian podcasts.

    With baking, green banana flour is about 17-25% RS3 later. Not bad! I love GBF — it tastes like spelt to me.

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