Resistant Starch: Your Questions Answered

PotatoesLast week’s Definitive Guide to Resistant Starch garnered a lot of attention. While the article covered a lot of ground, many of you had lingering questions and concerns about the topic: What is and isn’t resistant starch? How much resistant starch should I be eating? Why is resistant starch good for me? What is resistant starch again?

I don’t blame you; it’s a confusing one that appears, on first glance, to challenge some of the fundamental Primal ideas about food and nutrition.

Today, I’m going to answer as many questions from last week as I can. Hopefully it clears up most of the bigger questions.

Let’s get right to it:

Do the benefits of RS outweigh the negatives of rice, legumes, potatoes, etc.?

Great question.

Rice and potatoes, yes. I’ve already spoken on both those subjects in previous posts, and my basic conclusion is that both rice and potatoes are relatively toxin-free sources of starch that an insulin-sensitive, sufficiently-active individual can likely consume in moderation without ill effect. For both foods, the negative effects come from the carb load they represent, which is simply too high for some people. But by cooking and cooling them, you reduce the carb load, reduce the glucose response, and improve your insulin sensitivity. In essence, any “negatives” are mitigated by the emphasis on resistant starch. If you have trouble with glucose tolerance, and you’re looking to drop weight, you should still exercise caution with these foods and heed the Carb Curve, but preparing them in a way that increases the RS content will only make them less problematic.

One note: potatoes are iffy for people with nightshade intolerance. So there’s that to consider.

Legumes, I’m not sure. I strongly suspect that the health benefits ascribed to legumes are solely due to the prebiotic, RS effects, which interest me but are not the sole province of the legume. But the fact remains that many people simply don’t tolerate legumes very well. It could be that some of the tolerance issues stem from disrupted gut flora and introducing RS will ameliorate your troubles, but who knows? We’re still learning a lot. In the meantime, I’m not too interested in soaking beans. There’s nothing essential about them, so long as we’re getting RS from other sources.

I’m a little confused…how does one go about adding RS in whole food form without doubling or tripling their normal daily carb intake? I can’t see eating 1-2 green bananas and a couple raw potatoes each day, in addition to normal amounts of carbs from veggies and fruit (I usually have one serving of fruit a day– berries, if possible) and still staying under 100-150 carbs. Please, enlighten me!

Believe it or not, you can easily eat green bananas without tripling your digestible carb intake. And that’s the key: you don’t digest these carbs, your gut flora do. An average large banana contains a hair over 30 grams of carbohydrate. If it’s green and totally unripe, the majority of that carbohydrate will be resistant starch that your body does not digest into glucose.

You’ll know you’re getting the good stuff when the banana is crispy and leaves a chalky aftertaste in your mouth. Pleasant, I know. But added to a smoothie, it’s actually quite nice. In fact, here’s a recipe I’ve been playing around with:

  • Cup of milk (coconut, almond, cow, goat, etc)
  • Large green banana, peeled and sliced
  • Quarter teaspoon of vanilla extract
  • Quarter teaspoon of cinnamon
  • Half teaspoon of honey (may be unnecessary depending on the sweetness of your bananas)

I assume that the time of day you take RS does not matter?

It shouldn’t. Once you’ve established a healthy population of butyrate-producing gut bugs, they don’t need to be fed at a certain time every day. They’re quite malleable and adaptive, and they’ll also begin feeding on other fermentable fibers in your foods.

What is the reason to supplement RS instead of getting it from food? How much RS is “good enough” and how much real food would meet that amount?

Supplemental RS is just easier, and most of the research in support of it has used supplemental RS-rich powders – so we know it works. But real food probably works even better since it comes with vitamins, minerals, and polyphenols (which have prebiotic effects in their own right), and it most closely resembles the way our early ancestors consumed RS.

Let’s see. If you can work your way up to between 30 and 40 grams of RS, whether from food or from powders, you’ll be in a good place. That’s the dose used in much of the research, and it’s where butyrate production is maximized.

What does that look like in food form?

600 grams of baked, then cooled, potato has around 25 grams. You can even lightly heat the potato after it’s been cooled and retain the RS.

1 large (8 inch) green, fully unripe banana has somewhere between 20-25 grams. A large green plantain has about 50 grams. Not the most palatable, but it’s doable, especially if you slice into discs and dehydrate into chips. A smoothie masks it well, too.

Any idea if heating the potato starch (like using it as a thickening agent in soups/stews) negates its RS function?

Yes, the RS will be completely negated. Sorry. It does make a good thickener, though.

Cooked and cooled rice – as in sushi? Or does the vinegar somehow negate the benefit of the resistant starch?

Yes, cold sushi rice will contain RS. Good sushi restaurants generally keep their rice at room temperature, though, so I’m not sure you’ll get the retrograde RS effect unless you go for grocery store deli case sushi. And hey, I actually like that stuff, so there’s no shame in eating it. Just avoid gas station sushi if you know what’s good for you.

Vinegar shouldn’t affect it either way. Vinegar does reduce the blood glucose response when consumed with carb-rich foods, so it might be a nice supplement in its own right if that’s an effect you’re after.

So that pizza crust recipe has mostly tapioca starch/flour (same) in it. (Also, not Potato Starch–potato flour) If I make the crusts and freeze them and then reheat and eat, would the RS still be usable? Same as the potatoes and rice I would think. So perhaps that is a go on the RS.

I don’t think it works like that. For retrograde RS to form, it has to be in its whole form – potatoes, not potato starch; cassava, not tapioca starch; rice, not rice flour.

Question about “cooked and cooled” – what the heck does that mean? So, I cook it, and cool it. Does that mean I have to eat it cold to get the resistant starch? If I zap my bowl of bean soup and rice that came out of the fridge, when does it lose the resistance to digestion?

Retrograded RS (cooked and cooled) is maintained during subsequent heating. You can even heat it and cool it once again to create even more RS. So you don’t have to eat it cold, though I would advise against re-heating a cooked and cooled RS source into oblivion. Keep the heat relatively low.

Should the carbohydrates from resistant starches (for example, a cooked and cooled potato) still be counted in daily consumption if it is not digested?

Some of it should still be counted, because not all – or even most – of the starch is resistant. Most of it is good old digestible glucose. But you can subtract the 4-5 grams of RS from the 21 grams total starch in every 100 grams of cooked and cooled potato. Not bad, eh?

And remember, it’s not that the 4-5 grams become inert, useless matter passing through your body. They are bioactive, just not with the biology of the host. They turn into fatty acids that fuel your colon and improve your ability to tolerate the digestible glucose you consumed along with them.

Is just eating Pistachio’s (or other seeds) enough RS to do the trick?

Probably not. To hit the 30-40 grams of resistant starch that maximizes benefits in most trials with pistachios would require a lot – of money, of calories, of shelling. 100 grams of roasted pistachios has around 3.5 grams of RS. That may be in the shell, and raw pistachios may have more, but either way it’s not a huge amount. Not bad, not great. The beauty of the less calorically dense RS sources is that they allow a more varied diet. It’s nothing to add a couple tablespoons of potato starch to your diet.

That said, pistachios are potent prebiotics. One recent study found that they increased butyrate-producing bacteria in the colon, outperforming almonds. You should definitely eat pistachios, but I think you should also eat other more concentrated sources of RS.

That’s the beauty of it all: it’s not a competition! We can eat pistachios and other things at the same time without disrupting the effectiveness of either.

Question: would hummus fit the bill as cooked & cooled legumes?

Yes, hummus seems to qualify even though it’s not Primal. According to the PDF from last week’s post, 100 grams of hummus has 4.1 grams of RS. Hummus made from soaked chickpeas will have more than hummus made from canned chickpeas, however.

What would be the best way to gradually incorporate RS into the diet for a person that has gut inflammation with chronic bloating?

You need probiotics. And in your case, I doubt yogurt or even kefir will be sufficient. Try something soil-based, as in the same types of probiotic organisms that Grok was getting on a regular basis simply from living. These are likely the microbes to which our guts are evolutionarily accustomed.

Primal Flora works (worked for me with RS!); it provides a high dose of two specific soil-based strains that have been shown to be helpful in clinical trials. You could also go more broad-spectrum, with more soil-based strains but lower concentrations.

Start really, really, really small with the RS. If you’re going with the unmodified potato starch, start with 1/4 to 1/2 a teaspoon. It will look like almost nothing. Increase it by 1/4 tsp slowly as comfort allows.

If that doesn’t work – but I imagine it would – and your gut is really compromised, I suggest trying Dr. BG’s gut healing protocol. It involves probiotics, prebiotics, and a number of other, more drastic but potentially necessary steps. The good doc is a bit wild, but in a good way. Just read her stuff at least twice and you’ll figure it out. Reading it out loud seems to help, too. She certainly has a way with language!

Does this mean I can start eating sushi and potato salad??! 😉

Well, you can choose to eat anything you want, of course. That’s never changed. What this does indicate is that those foods, when cooled, have unique effects, different than if you were to eat a bowl of hot steamed rice or a large baked potato fresh from the oven.

The preponderance of evidence suggests that the potato salad and the cold sushi rice will result in a lower blood glucose response and feed the helpful critters in your gut – both good things. But before you go digging into that store bought potato salad on a regular basis, consider avoiding the seed oils and making your own. I’m a fan of lemon juice, olive oil, salt, and fresh herbs, myself. I can rarely be bothered to make my own mayo, although that’s also a good option.

Anyone have a recipe using raw potato starch that can be easily incorporated into a primal/paleo diet (meat, eggs, veges, occasional fruit)? I don’t do smoothies, nor do I do fruit juice or yogurt.

Aside from smoothies, sparkling water is the best vehicle I’ve found for potato starch. The bubbles seem to enhance the dispersal of potato starch granules into the medium, even without a blender. Just a fork or even a quick stir with your index finger is enough to get it completely mixed in.

So what to use? Bob’s Red Mill Potato Starch or Bob’s Red Mill Tapioca Flour?

Potato starch seems to be the most reliable way. From reading the comment sections on blogs and posts on various forums, the digestibility of tapioca starch/flour varies from person to person. Many people seem to get elevated blood sugar after taking a tablespoon or two of the tapioca, whereas potato starch is almost invariably indigestible.

Can the potatoes be fried in lard and then cooled? I would rather try a yummy food source then a powder.

A few weeks back, I described my method for foolproof, easy crispy root vegetables. You pre-bake them and store in the fridge. This increases the RS content of the potato. When you’re ready to fry them, simply peel the skin, cut them up into the desired shape (cube, fry, etc), and lightly pan fry them in the fat of your choice. Lard is a great option. Since they’re already cooked, you don’t need a lot of heat or a lengthy cooking time, and the RS is preserved.

If we’re taking probiotics without RS as well – what is happening? The bacteria in the probiotics are starving? But don’t they eat other stuff besides RS? Sorry, I know I sound like a boob, but – I’m still a little confused.

No, the probiotics can still help, by partial colonization. But for the best results, you’ll want to provide food so that the probiotics have more lasting power and can hitch a ride into the colon where they do the most good. Feed the animals; they aren’t bears and it’s not Yellowstone! It can be resistant starch and/or any other prebiotic fiber. The point is to feed them stuff they can eat, thrive on, and ride on.

RS fits the bill.

One more question – how does this need for RS fit into the Grok-lore? What did our Paleo ancestors do that we aren’t doing?

As I’ve written before, wild tubers, roots, and other underground storage organs are frequently highly fibrous with lots of indigestible starch. That’s what Grok would have encountered, not the smooth, starchy goodness of a Russet potato, which had to be selected for by the experienced hands of agrarian tuber breeders.

We can’t all eat dirt-encrusted cattails rich in resistant starch, but we can approximate the effects with modern tools. Taking soil-based probiotics and emphasizing preparation methods that maximize resistant starch content is, by all accounts, an extremely Primal and biologically-appropriate way to emulate one important aspect of our evolutionary metabolic environment.

Any thoughts on the resistant starch found in Quest Bars? Quest Bars contain isomalto-oligosaccharides. The makers claim this is a resistant starch.

It’s not a resistant starch per se, but rather a prebiotic fermentable fiber. Studies indicate that while its consumption does improve constipation and increase production of the short chain fatty acids (SCFAs) propionate and acetate, it does not increase production of the most beneficial SCFA, butyrate.

Is consuming RS the only way to feed our gut?

No, definitely not. Other prebiotic substances matter, like various plant fibers (inulin, pectin), dark chocolate, and even connective tissue (yes, animal fiber – the crunchy gristle and cartilage too many people discard). With a Primal eating plan rich in plants and whole animals (including bones and broth), you should be getting plenty. But resistant starch is an important, unique prebiotic that makes feeding our gut a whole lot easier and more effective.

That’s it for today, folks. Thanks for reading!

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About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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236 thoughts on “Resistant Starch: Your Questions Answered”

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  1. Thanks for the answers. I recently started taking resistant potato starch myself… haven’t noticed anything yet, but I started low due to a sensitive gut. Any thoughts on potato starch and nightshade sensitivity? I know that Mark has mentioned in previous posts that too many potatoes have made his joints ache. I’ve also suspected nightshade sensitivity occasionally…but it’s near impossible to pin down the exact sources of gut problems sometimes!

  2. That’s wonderful–I love green bananas but I’ve always been afraid of the carbs. The sugar might still be too much for me, but now I have a great roadtrip snack.

      1. As I learned from my FM son, the fructose in a green banana is much lower than in a ripe one because the starch has not yet converted to sugar.

    1. I’m not a fan of green bananas, but I have been known to get impatient and eat one every now and then. 🙂

    2. Green bananas are a great way to experience resistive starch. dont worry about carbs because they dont go through the insulin process. I take 2 hard green and 2 yellow throw in blender with coco water with no added suger and a teaspoon of ceylon cinnamon or real cinnamon which i get in sticks and grind fresh . dont use cassia cinaamon as is very bad for your liver. i also throw in a love of garlic . Have been doing this 2xs a day for 3 months now and it is amazing how good I feel. good luck

  3. We must be resistant to resistant starch–all I get is weight gain. Hubby’s BG goes through the roof and mostly stays there.

    1. As I understand it, then, it’s not RS you’re getting, but digestible starch–because RS isn’t digestible, it doesn’t send the BG up like that. What was your source?

    2. @Wenchypoo — Others seem to echo your experience. Since we don’t all handle carbohydrate the same, it stands to reason that we don’t all handle resistant starch the same way. Here’s a link to a study that may provide genetic clues to differing carbohydrate metabolism from Kresser’s site:

      Those with low copy number of amylase gene would likely fare better not trying to emulate the starchy diets (resistant starch or otherwise) of Asians/Africans.

      Just as some vlc zealots believe everyone on the planet should be in ketosis, it appears that some resistant starch zealots believe that they’ve found the holy health grail and that those who don’t believe are a ribeye away from doom and gloom. I’m reading things like billions of Asians can’t be wrong blah blah blah. I don’t think they are wrong, they just may be genetically better adapted to higher starch fare.

      I like Mark’s measured approach — experiment and see what works for you (which it appears you have done) and ditch what doesn’t.

      1. whmmmmm if a person is eating normal meals and only one resistant starch meal there may be problems. What I did and do is eat 2 resitive starch smoothies a day and one normal meal but low on carbs and cut the suger compleatly. never felt better am 65. RS has cut all food cravings for me. Its a great experience. Am dropping fat dramatically.

    3. @Wenchypoo, a lot of us gain about 5-10 pounds as when you feed the bacteria they grow at an enormous speed. I always wondered how 4 oz of rice could add a pound of weight over night. Now I know – the rest is water used to grow the increased numbers of bacteria. I decided the potential long term health benefits of adding RS would negate the worries about the added weight. Starving the good gut bacteria which supports the immune system also makes blood sugars overly sensitive (ie go sky high with any sugars). After 5 years on a moderately low (not VLC) carb intake really, really mucked up my blood sugar responses as measured by symptoms. After 3 months on RS I can say that while my weight is up I’ve not had to buy new clothes (though at the top of my range), my sleep is MUCH better, my blood sugars by symptoms are vastly improved. So overall I reckon its worth it despite me being one with multiple health issues. I feel I’m on the right track.

    4. Because it’s all baloney. R.S. i s a dangerous myth…dangerous that is for any type 1 diabetic thinking they are going to lower their glucose levels doing this.

  4. Can I leave here a (traditional Spanish) recipe for mayonnaise?
    So often mayo is referred to as something cumbersome to do. But there is probably not an easier sauce to fix. It takes literally seconds. And is completely primal.

    This is the typical Spanish home mayonnaise. You need: One egg, olive oil, lemon (or vinegar), salt.

    Put the egg in a mixing glass. Using an electric mixer start mixing with one hand while with the other you slowly pour the olive oil. Stop once you get a slighter thicker consistency than you want. Squeeze is some lemon and salt. Mix again. Voila!

    1. I highly recommend using the stick blender method. Youtube has a great one minute mayo video but basically you put all your mayo ingredients in the blender glass and let them settle. Then start pulsing from the bottom slow and brief for several pulses. When the mixture starts to emulsify in the bottom, you can begin mixing more earnestly until all the oil is incorporated. A super-fresh pastured egg and good olive oil will make the creamiest, most delicious mayo! Coconut oil tends to get hard again in the fridge. Experiment with various vinegar and lemon juice combos and adding garlic powder and dry mustard. Anchovy filets also add a kick like you wouldn’t believe!

      Yay! Potato salad for summer!! I am so glad!

      1. FYI, melted bacon drippings makes fantastic mayo with the above method. You’re welcome.

    2. Olive oil mayo has always come out horribly bitter. If I use the “light tasting” olive oil I worry about how it has been refined & deodorized & bastardized.

      1. I like veganaise but a friend told me about lemonaise and I am going to try that (not sure about the spelling of them…)

      2. I have that problem when I use “good” EVO — it’s just too strong. Now I make mayo from EITHER: Avocado oil or MCT oil (does not get hard in frig) or a mixture. A Cuisanart even comes with a hole in the lid for making easy mayo — it’s a snap! Tip: both the egg & oils must be the SAME temperature.

  5. So would it stand to reason that the best way to do Primal Flora would be to take the capsules with some sparkling water with potato starch stirred in?

  6. And it’s all compiled in one spot…Mark, you’re just awesome. Thanks.

  7. Yikes, confused:

    “I don’t think it works like that. For retrograde RS to form, it has to be in its whole form – potatoes, not potato starch; cassava, not tapioca starch; rice, not rice flour.”

    But I thought previous entry had encouraged adding potato starch powder? Uh oh, I’ve been doing it for a few days now (nothing major, just a half tsp).

    anyone? potato starch powder (like bob’s mill bagged) ok in morn drink?

    1. Potato starch powder is ok, just don’t heat it.

      The question is referring to Retrograde RS, which you get from cooking and then cooling.

    2. I was just going to post the same question. This is an awesome post overall, but that point has me VERY confused. Thanks for asking Suzanne and I hope someone can answer…

    3. My question has been about refrigerated baked goods with Green Plantain Flour. I understand the point about “whole vs processed”, but I read a study (cannot site it now) where they measured RS in cooked, cooked & cooled, as well as cooked, cooled, & reheated Wheat PASTA. There was a significant amount of RS in reheated pasta — definitely a “processed” food. So I am also confused & looking for an answer.

      1. Id really like to know about baking with plantain or green banana flour. Would it be safe to bake say a cake with that, refrigerate and then consume? Or will that be digestible starch?

  8. Thanks for putting this all in one place, Mark.

    My wife and I do a nightly kefir smoothie. Adding a fully green banana to the mix is no problem at all.

  9. So…fried plantain chips don’t work? Bummer.
    Time to get out the yogurt and go for a funky smoothie…O.o Don’t have a dehydrator unfortunately.

    1. Use the method that Mark mentioned regarding potatoes, it should work the same. Bake, cool in fridge, then fry.

      1. heating the plantain destroys the resistant starch. SB, you can put the plantain chips in the oven with just the pilot light on and it will dry them out in about one day depending how warm your oven is. You can even raise the oven temperature by putting an electrical chord with a light bulb on the end inside your oven with the other end plugged into a socket and the light bulb will raise the temperature inside your oven about 10 degree, if you have no leaks in your oven. I have 2 panels in the back of my oven with cut outs, but the plantains chips were dried anyway in 24 hours. I didn’t continue drying plantain, because it still tasted like chalk. Probable if I mixed the plantains with coconut oil or grass fed butter, it would taste better. But I have a major issue with my teeth and I’m worry that plantains may contain high contents of phytates. I have not been able to find out if they do, but I did notice that a cracked tooth I have becoming more sensitive and eventually cracking more. I would really appreciate it if anyone can tell me the phytate content of Plantains. Thank You.

  10. Hi, Firstly thanks so much for this site and all the brilliant info and inspiration. I would like to ask a question. I followed the McDougall (high starch) diet on recommendation for the reduction of arthritis and weight for about three months last year – made me worse, a lot worse! Also made me weak and very light headed. Then I discovered professor Ebringer’s London Diet (low starch) which has been, in the main, very helpful. The theory is that it starves a certain microbe called Klebsiella pneumoniae, thought to cause a leaky gut and an autoimmune response that breaks down joint tissue, which I think was causing my symptoms. I also tweaked my diet after finding Sarah Ballantyne’s book and on finding this site and your books, I am just starting the 21 day Primal Blueprint programme. My question is, do you have any thoughts or information on how to starve these bad organisms by avoiding RS, yet keep up the good organisms by eating fermented foods, yet they also need RS to grow? It is something of a dilemma. Thanks again:)

    1. My understanding includes the following:
      – Different microbes often feed on different things, and most can feed on multiple things. Most of them do not feed exclusively on RS, and some do not eat RS at all. Much overlap and adaption of course (even borrowing/copying genetic material from other species!), but you can change the demographics of your microbiome dramatically by changing your diet.
      – Intermittent fasting may help by weeding out some of the undesirables. It has other benefits, too.
      – In general, biodiversity is good. Having many species keeps all of them in check, especially the aggressive ones (the potential pathogens). It creates an ecosystem.
      – In a healthy, diverse gut population, I imagine that those species that are “not supposed to be there” would tend to die off and have a very hard time colonizing. This because a healthy, diverse (=stable, strong) population would be the one with which symbiotic relationships developed, and so “good” or “bad” species would be defined by their membership or lack thereof. *This is entirely speculation*
      – You can start mostly from scratch by taking antibiotics, and then probiotics. However, this gives pathogenic species an outstanding opportunity to set up shop. Unrecommended extreme measure; choose your probiotics wisely and choose lots of them.

  11. anyone here use something different besides primal flora for their probiotic?

    1. Also, I regularly drink kombucha. I am wondering if I should add a capsule or not.

        1. I’m also taking Prescript Assist and AOR-3.

          I take 4 tbsp. of Bob’s Red Mill unmodified (raw) potato starch a day.
          I am fine with just mixing it in water and chugging it down, but sometimes I liked to mix it into some organic canned pumpkin (at room temperature) along with some cinnamon, pumpkin pie spice, and some sweetener (stevia or Z-sweet).

          I’m a diabetic on insulin and I am getting the best fasting bg’s I have
          ever had in 20+ years! Yay!

    2. Make your own Kimchi! or sauerkraut. It is easy and fun and interesting to make. I use Sally Fallon’s, “Nourishing Traditions” recipes. I highly recommend the book for its many, many wonderful fermented food recipes. I have seen many posts on youtube as well that will talk you through the process.

    3. VSL 3 from Sigma Tau. Expensive but is high potency. Recommended to us by an integrative MD. Does not require a prescription. Our local pharmacy orders it for us but you can also get it directly from the company. Look online.

      1. VSL is one of the few that has been studied & “proven” to make it thru stomach acid & colonize to a certain extent. There are a few others, but hard to buy. I found some on — plus Dr. Douillard has a good “complete program” designed to “populate” your gut with good bacteria.

  12. If I just eat raw peeled potato to get my RS, is there a better choice regarding what type of potato to eat and also what amount would be best? I have been eating a quarter of a medium sized russet potato so far. Thnx.

    1. I read that Russet potatoes are highly digestible, not as much RS as a waxy type or potato, like Yukon Gold. Also, it’s best to cook the potato whole, so that it doesn’t take on a bunch of extra water. The extra water gets in the starch molecules so that they can be formed into amylopectin, which is highly digestible. Without extra water, starch molecules can cool to form the tightly wound amylose molecules, which is what resistant starch is. So, by my understanding, less water and less cooking are better, but steaming, boiling, roasting should all be fine for potatoes.

      I use my slow cooker a lot, and here’s my trick. I have meat and or bones cooking, and then set small whole, waxy potatoes on top, so they’re barely in the liquid. I just take them out when they are done, let them cool, refrigerate at least 24 hours before eating.

      I’m a diet-controlled diabetic, and I added Bob’s Red Mill potato starch for my diet for 2 weeks, 4 tbsp per day, divided into 3 meals. I started reading about persorption of starch molecules, wondering if there’s any truth to articles saying that starch molecules can migrate all over the body and cause micro-embolisms. So now, I’ve decided to stick to going more natural–green plaintain and cold potatoes. So far, I have been able to eat 50g of cold potato with my blood sugar only rising to about 120, which is GREAT for me! Usually, that’d be 140 or even 160!

    2. I use purple potatoes. There are a few varieties that your local hippy grocer may have. I figure if I’m going to eat something starchy, I may as we’ll take in some antioxidants with it. No difference in flavor though.

  13. Does a steamed, then cooled sweet potato (orange flesh variety) have a lot of RS, or are regular potatoes better?

    1. Sweet Potatos have little to no RS. White potatoes are the way to go however not via steaming

        1. From what I’ve been reading, roasting potatoes is the best method. Simply cut the potatoes (skinned or not, you choose), coat them lightly in oil (or not, you choose), pop them in the oven at 400 degrees until cooked but not soft, more al dente like. Then, cool them in the fridge overnight (these actually should last 3-4 days if you want to make a larger batch). Bring them out in the morning and pan fry them lightly (just to heat them, don’t get them piping hot!) like Mark suggested – in a little lard or fat of choice. Then, cook a couple of organic eggs sunny side up and toss those babies on top. Perfect breakfast, IMO, or lunch, or dinner (you choose). Add a little sauteed kale to that plate and yum, yum, yum. You could also cut up the potatoes and add them to a skillet of sweet potato hash browns (already cooked through and hot), turn off the heat and just toss it all, making a combo nutrient dense, RS packed power meal. Personally, this is my plan for on days I ride a bike over 30 miles or hike for several hours. It’s rocket fuel, I swear!

        2. Thanks for the recipe! However, I’m still curious to why steaming would not work as well as roasting.

  14. I was under the impression inulin is resistant starch. Is this incorrect? Specifically Jerusalem artichokes (aka sun chokes). Thanks

  15. Don’t know much about RS but that has not prevented me from achieving some benefit from Mark’s “21-day” program (for 4 months now): weight 205 from 224, trig from 159 to 94, hdl from 41 to 47, ldl from 139 to 109, only stubborn glucose remains high (112-113) on fasting test. Doc sad, keep doing what you’re doing, before her training overcame common sense and she started spouting SAD advice: low fat, hi grains, etc. Ha. And my blood pressure went from 125/85 p65 to 98/65 p50!

    1. Your blood sugar is higher because you’re on a very low carb diet. I know it sounds backwards but it happened to me while all my other numbers looked perfect. Your becomes insulin resistant when you’re low carb to save glucose for the brain. This is totally normal to have higher morning blood sugar but it usually normalizes torwards the afternoon and night.

    2. The high fasting blood sugar is probably due to a fatty liver from a long time with low fat high carb eating, visible in your earlier high triglycerides. Intermittent fasting, maybe 3 days water fast in a row over a few weeks will reduce it, at least for me it went from.120 to 100 over 3 weeks with 5 day water fast per week!
      The reduced insulin resistance showed up in lower fasting insulin also.
      But your blood pressure reduction with resistant starch is really inspiring, to say the least! I will increase the potato flour now!

  16. I do not understand this issue with hot or cold RS. Doesn’t everything become body temperature once it stays 2-3 minutes in the stomach? :S

    1. It stays resistant up to about 140 degrees F. Above that, it degrades into starch that the small intestine can process.

      1. When I eat a hot potato, I would think that my body begins to cool it immediately from mouth to stomach before it enters the small intestine such that anything reaching the small intestine is roughly 98.6 degrees, no?

    2. The original blog entry states that raw potatoes are a good source of resistant starch, but not many people like to eat raw potatoes, so powdered potato starch is offered as an alternative.

      Cooking the potato greatly reduces the amount of resistant starch, but once cooled “retrograde” resistant starch is formed. So that’s why you get more resistant starch from a potato that’s been cooked and cooled than from a hot one. According to the blog entry above, once the retrograde resistant starch has formed, you can then reheat the potato without losing any more RS.

      In short, when it comes to potatoes, if you want the most resistant starch:
      – raw potatoes
      – uncooked potato starch
      – cooked and cooled potatoes
      – cooked and cooled and reheated potatoes.
      Don’t eat:
      – cooked potatoes
      – cooked potato starch

      1. Do you have any idea how much RS is in a raw potato? I’ve been slicing them up and throwing them in my salads. It really makes eating them very easy!

  17. Another question: can you get soil-based probiotics simply by letting the food from your garden stay a little dirty before you eat it raw? Or maybe even eat a little dirt?

    1. If you’re growing your own veggies, you’ll probably get plenty even if you give them a light rinse. Especially if you’re not peeling or cooking them – carrots, radishes, turnips and other root veggies that can be eaten raw, also most of the leafy greens eaten raw. They have lots of nooks and crannies that harbor microflora that a light rinse won’t dislodge.

  18. I’ve been taking potato starch (4 tbs daily, split into 2 servings) for about 6 weeks and find that my sleep quality has improved. I recently went off the stuff for 2 weeks due to abdominal surgery — I wasn’t eating anything for a few days and was slow to get back into the routine. My digestion was poor after all the antibiotics and pain meds, but starting back on probiotics and potato starch seems to be helping after just a couple days.

  19. Maybe a silly question but – if I freeze the green bananas, do the retain their unripe state?

    1. I peeled green bananas and plaintains, sliced and then refrigerated or froze in open containers. (No lid.) They dried out in a way that I liked, and still seemed to retain their unripe state–didn’t get sweet.

  20. Is there any difference in RS between white potatoes and sweet potatoes?

    1. Mark put a link to a PDF in this article. Please go read it, as it will tell you how much RS is in food (very helpful). No, sweet potatoes don’t have much RS at all, but that doesn’t mean you should chuck them entirely for the white potatoes. Sweet potatoes have so much more nutritional value and are still very valid in our diets. I still eat them and am using potato starch on the days I do (i.e. I’m aware of carb content so I rotate sweet potatoes on the days I use PS; and on the days I eat white potatoes (cooked & cooled), I don’t eat the sweet potatoes – unless, I do a combo mix, but even then, I stay cognizant of the carb count)

    2. Sweet potatoes contain hardly any RS, so don’t waste your time eating that. You could replace either one with Jicama – excellent stuff. Low GI, GL, contains inulin – polysaccharides a much desired prebiotic/fiber. Jicama is aka “yambean”, “turnip” (in Asia), Mexican yam, etc.

  21. Great information as usual.
    It becomes unfortunate though that our severely depleted and overused soil for food based sources just don’t have the nutrients in them that they should or even close to what are paleolithic ancestors would have had access to

  22. Why is no one talking about chia in this latest round of RS droning? A “smoothy” of kefir, chia, cocoa, homemade kraut juice…..mmmmmmm.

    1. Sorry Fred, you had me until the kraut juice! Ugh, to each his own, but that sounds like a “gawd-awful” concoction!

  23. I started a week ago with tapioca starch as I have nightshade problems. I had gas the first day, then no problems. I am now up to 4T/day having worked up slowly. I love the satiating effect of RS. I will try this for a full month and see if it seems to be doing anything. Thanks for all the articles on this subject, this is very helpful to me, and many others…from the volume.

    1. From what Mark said in response to soemone asking about tapoica starch I believe there is very little resistant starch in tapioca, if you can’t have potatoes then you might be better off with green bananas or plantains

  24. So if I am understanding this, as summer approaches (BBQ season!), German potato salad is the way to go. Cooked and cooled potatoes and vinegar instead of mayo. I can live with that.

    1. Why vinegar instead of mayo? If it’s because of the vegetable oil just make your own with olive oil, it’s very easy, much easier than people make out, although does take a lot of whicking if you do it by hand. But hey, that’s exercise!

      1. How does olive oil hold up? Even overnight in the refrigerator and mayo gets weird. I would make a tub and eat it all week and I think vinegar would hold up better. I do prefer mayo, so it has been YEARS since I had German style, I think I’ll make some this weekend. With bacon of course.

      2. Why vinegar? Because that’s what’s in the traditional German potato salad recipe. Generally some sort of oil too. Although every German potato salad I’ve ever had has been served warm.

      3. Every olive oil mayo I’ve ever made is horribly bitter and had to be tossed.

        1. I have to admit I don’t use extra virgin olive oil for mayo but a refined one for this reason, still much better than the vegetable oil ones though! You could alos use high oleic sunflower oil if you can get hold of it

        2. Try avocado oil (or macadamia nut oil if you’ve got a little extra cash – it’s pricy!) Virgin or extra virgin OO is not good to make mayo with.

  25. Does it make you a little nervous to proclaim that butyrate is the king of the SFCAs and the preferred product in the netherends? I mean, there was a time where everyone thought glucose was supreme for the brain, but ketogenic diets are doing wonders for people. I’m just not sure we’re ready to declare that butyrate is king yet, are we?

  26. Amazing information as usual. Thank you. Would Chicory Root or Artichoke inulin powders be considered RS?

  27. I wonder if the plantain pancakes I make have much RS? They’re made with green plantains and eggs, butter vanilla, than cooked but I sometimes make extra and put them in the fridge and reheat the next day. I understand the green plantains need to be raw for best effect but if they’re cooked and then cooled wouldn’t you get the retrograde RS? What about if you cook them and let them cool before eating them (with handling a 4 year old and getting food down her my food is often cold before I get to it!),

    Also, glad to know that my occasional potato salad is a good thing!

  28. Although not primal, are frozen peas, ie raw and frozen, a good source of resistant starch?

  29. I think there should be a distinction made between Bob’s Red Mill potato starch and Bob’s Red Mill unmodified potato starch. They are two different products. I am assuming the “unmodified” means “raw.” I don’t think regular potato starch includes any resistant starch, but unmodified potato starch does? Please correct me if I’m wrong.

    1. Use Bob’s Red Mill Unmodified Potato Starch. I’ve been putting a tablespoon in a smallish glass of cold water, stirring just a bit to dissolve, and drinking. Twice a day. Seems to work fine without a lot of expense or fuss, although I now realize I should be taking about two times as much as I am now.

  30. Here’s a great recipe I use to add unmodified potato starch to my diet. Chocolate “Pudding”
    1 avocado,
    1/2 banana,
    1 T natural unsweetened cocoa powder,
    about 1/4 C milk or water (almond milk, dairy or whatever you like. Just enough to be able to blend the ingredients)
    1 t unmodified potato starch (or however much you like),
    few drops of stevia or sweetener of your choice (I usually use 1 packet of Truvia)
    Give it a whirl in your food processor or VitaMix. I use my VitaMix. Rich, creamy, chocolate treat! I make it a “functional food” by adding some VSL3 probiotics, potato starch, some calcium/magnesium powder out of a capsule.

    You could try making it with an immersion blender or a regular blender; might need a bit more milk.

    It’s a very flexible recipe! Sometimes I use just half an avocado. Adjust the ingredients to your taste. Chocolate and avocado sounded like a strange combo at first, but you don’t taste the avocado, just the chocolate and banana. It’s delicious!

  31. Thanks for answering my hummus question, Mark! There’s a Lebanese restaurant nearby that makes the BEST hummus ever, & I know one of their secrets is extra-long soaking, so I’m betting it is healthier than the run of the mill variety. It’s definitely tastier!

  32. Just tried mixing potato starch with seltzer, PERFECT, no lumps or potato taste, the first time I tried mixing with mashed avocado, worked but gummy, Thanks.

    1. I love my own home made Vichyssoise-cold potato soup-you have to boil the potatoes and put them in the refrigerator for a few hours to become resistant-so then make that into soup. For the raw potato starch (Bob’s Red…) I put it in a smoothie in the morning-unsweetened original almond milk, raw potato starch, chia seeds, flax seeds, sometimes some plant based protein, raw coconut milk (if on hand), soaked almonds, walnuts, pumpkin seeds, and sometimes a part of a green banana. It is a bit textured so I actually chew it (to mix with saliva for digestion) and mmmmmmmmmmmm.

      1. And for the resistant starch I make a kind of a rice pudding-I have to check if black rice would also be resistant but I use the Thai black sticky rice pudding and you can actually steam it in a Chinese pumpkin and make it cold in the refrig before slicing and serving. Or just make a regular rice pudding also.

  33. If you want a cookie-dough like RS mix, take:

    4T Bob’s Red Mill Potato Starch
    2T Raw Almond Butter
    1T Butter

    Mix it!

    Delicious alone or with celery or however you want to eat it. I think all told it’s only about 400 calories (ok, that’s a lot), mostly from fat or RS-which-is-eventually-fat.

    1. This sounds really yummy. I don’t think 400 cals is really THAT much… in context. I mean if you ate this all day long every day… that’d probably cause some problems. But as an occasional treat it’s probably fine. How often do you eat this, if I may ask, Justin?

      1. Yeah it’s not really that much — I used it as a sorta light lunch to break a fast. This was done maybe 2-3 times a week.

        FWIW I never had much of an issue with gas, but had been taking a probiotic for awhile. I can attest to the vivid dreams though.

  34. I still am not really hearing an answer to my question which is “If I just eat raw peeled potato without cooking it in any way shape or form to get my RS, is there a better choice regarding what type of potato to eat and also what amount would be best?” I have been eating a quarter of a medium sized uncooked raw russet potato so far. Thnx.

    1. Please don’t eat raw potatoes, they are very toxic. You can get very sick or even die.

  35. I am SO scared to try probiotics again. A couple years ago, I bought some refrigerated kind at Whole Foods. Took one capsule the first evening, a second at midday the next day and then spent the next two weeks unbelievably sick! I lost 17 pounds in 10 days (and NOT in a good way! It seemed as if all my gut flora and fauna took a mad dash for the emergency exit!) So, so ill! The company never answered my emails (I wondered if the stuff had been contaminated); and I’m nervous about trying some again.

    I have no bad reaction to the potato starch — I enjoy the vivid dreams! I take 4-5 TBL every couple of days. However my diet sucks: I hate all vegetables (I have since infancy) and tend to live on meat, eggs, rice, cheese, and nuts, mainly. (Yes I try veg now-and-again — and still recoil from the taste. {sigh}) I bought some Primal Defense after the previous entry, but am leery of trying it — trying to figure out a time when I can afford two-week downtime, just in case…

    1. It’s possible you got a bug, perhaps from going out shopping or whatever. It’s happened to me a couple of times in the last 3 years and is very debilitating. Most people take probiotics without difficulty…however, maybe you could try opening a capsule and sprinkling just a tiny bit of the contents in your potato starch, just in case.

      A healthy gut biome requires food in the form of a variety of fibers and other prebiotics such as RS, inulin, etc. Not eating any veggies or fruit makes that difficult, obviously. Maybe look up sources of prebiotics and probiotics and see if you can add any to your diet. Can you eat Bubbies brand pickles, kefir, psyllium husks, for example. One of the items I buy now are shiritaki “yam” noodles at an Asian grocery store, which are made are from the konjac plant and feed the good bugs. (Don’t get the tofu type. 🙁 )

  36. I’ve read about RS for a few years now and about how cooled baked potatoes are supposed to help one lose fat. I love cooled baked potatoes anyway

    BTW, who is the young man in the picture? He looks just like my son!!

    1. I heard that you can’t reheat potatoes or rice and it still is a resistant starch but if you put it back in the refrigerator a second time it is even better as a resistant starch.

    2. I understand the potatoes are supposed to be boiled then cooled in the refrigerator several hours or overnight to become rs. Also the rice has to cooled in the refrigerator several hours or overnight

  37. Please excuse me if this was answered before (I read last week’s post and this one), but if I were to elect to eat raw potato with some nice sea salt, how much raw potato would I have to eat to get the 30 – 40 grams of RS recommended?

    Thank you!

    1. Please don’t eat raw potatoes. They can make you very sick. There are many cases in the scientific literature of people actually dying from eating raw potatoes. Cooking destroys most but not all of the toxic enzyme (protease) inhibitors and lectins, but very little of the saponins (glycoalkaloids). The saponins are very high in green potatoes, which is why you can’t eat green potatoes, even if you cook, bake or deep-fry them. If you want to eat raw roots, stick to tried and true ones, such as carrots, and speak to people with a long, long experience eating others.

      1. thanks for the note about NOT eating raw spuds, Ben. I’ve just discovered a good replacement – Jicama (often called ‘turnip’ in Asia, and ‘yambean’ and Pachyrhizus erosus elsewhere). It has both low glycemic index and glycemic load. It contains inulin… and its innate sweetness comes from polysaccharides and not sugar, so helps provide not only diabetic-friendly food but also a much desired prebiotic/fiber

  38. Mark, I guess I got a little over exuberant after reading your article (definitive guide to starches). I made me a potato salad(with homemade mayo), let it cool and ate which turned out to be too much! My stomach was an issue for a couple of unpleasant days and I would have been better off heeding your advice to start slow with this stuff. Did I not have enough probiotics in my system to handle the large portion of potato salad? Oh well, I had a much smaller portion today and things seem to be holding up pretty well if you know what I mean.

  39. James Beard liked raw potato as an appetizer: sliced into rings, topped with sour cream and caviar. I never got to the caviar, but raw potato has been a guilty pleasure of mine since childhood. So glad to know I can come out of the closet. Raw, different kinds of potatoes have distinct flavors. Purple ones are my favorite.

  40. Several comments on this post by Richard Nikoley of freetheanimal address the nightshade question. One commenter who is very sensitive to nightshades has had no trouble at all with potato starch. Another commenter warned about possible risks with eating raw potatoes and said potato starch is much safer than eating raw potatoes.

    Here is a link — scroll down to see the comments on nightshades and raw potatoes.

  41. As far as food sources for RS go, what about Jerusalem Artichokes (aka-Sunchokes)? I cannot find anything one way or the other on this tuber.

    1. My understanding is that sunchokes are high in inulin, a good prebiotic, but not RS.

  42. I’ve been PS for five months. Lowered my fasting blood glucose by up to forty points, although it is back up a bit now.

    All these questions about eating this or that to get RS. You have to really work hard at that to get the 40 grams a day, and you will inevitably be bring along other, digestible carbs. Just buckle down and do the PS in water. It’s almost tasteless. There’s no need to hide it in that paleo blender smoothie.

    You can save a lot of money by buying PS at the Asian Market, literally a fraction of Bob’s at Whole Foods. Make sure you get starch, not flour. Starch will sink to the bottom of a cup of water and will not dissolve.

    Although most of the carbs in PS aren’t digested as carbs, they most surely have calories, if you are counting. The very first bag of Bob’s I got listed the calories as fats! I was amazed, then they changed it to conventional carbs. I use 30 calories per tablespoon as fats in my diet recording.

    1. {wince} My first consideration would be — what is the quality standard that Chinese potato starch is prepared to? Any melamine in it? Heavy metals? Other contaminants (intentional or not)? You can pretty well rely on the idea that the US govt is NOT bothering to/able to/intending to actually inspect any of it to see if it is contaminated. I expect that our primal/paleo/N=1 small group (compared to the whole American population) isn’t causing an unmanageable pressure on the producers to ‘make more’ but, as with any (apparent) fad, people/companies may rush in to make money by making product without a commitment to wholesomeness and health!

      (I hate to write that, but there it is! If “the Chinese” — that is, *some* producers, mfgs, and govt inspectors in China — will poison dogs here (and OMG! several hundred infants there!) with melamine in food or formula; how do we protect ourselves?)

      1. Elenor, you are jumping to conclusions. The potato start I buy clearly says on the label, “Made in U.S.A.” I presume Bob’s Red Mill is, too, but I’ve never learned if it is.

        Life has enough things to justifiably be fearful of. Don’t go making up invalid ones.

        1. Good to know your ‘Asian’ PS isn’t Asian.

          However: “Don’t go making up invalid ones.”

          Worrying about products made in China and not inspected on their way here for wholesomeness and health is not an invalid concern. (And, just as with stuff labeled “virgin olive oil” sometimes being partly or mostly canola oil — being “overly” careful may not be “overly” at all!)

  43. Waaaaiitaminute. So let me get this straight.. I can now cook rice in my rice cooker, then put the rice in the fridge, then heat it in the microwave when I want to… And that qualifies as RS? This sounds too good to be true. Am I understanding this correctly? ?

  44. Our biome is the result of what we eat, not a preexisting colony of bacteria that needs to be fed and taken care of like a garden. A diet that is animal based and extremely limited in vegetable matter will never need resistance starch as it will never have provided an every source for the bacteria that thrive on resistance starch to colonize our colon.

    The bacteria is the result of what we eat, not the reason to choose what we eat.

    And from the time a million and a half ago that we began cooking our tubers with fire we have not been regularly eating raw tubers. And, again, until the advent of sustained agriculture, vegetables were a limited part of our diet.

    I am in the carnivore tent. If you eat meat, fish, eggs, shellfish, and raw fat dairy if you can, you will never need a vegetable or fruit, or need bacteria that aid in their digestion . You only need the bacteria that help you to digest what you eat. This is the point, you only need the bacteria that naturally develops from the foods that you eat.

    1. Thank you, Michael. It is so hard to resist the “you MUST eat your veggies or DIE!” (and not from vegans but from our primal / paleo / LCHF brothers and sisters), that it becomes a steady drumbeat around food…

      In my family we joke that my older sister — the 40-yr-vegetarian — got all the veggie genes and I got all the meat genes! As infants, children, kids, and teens — our parents despaired because she HATED meat, and I HATED veg! Interestingly, SHE was usually released from table way sooner than I was — it was/is, apparently, more acceptable to refuse to eat your meat course than your veg course — well, that and she could slip it to the dog — who flat-out refused to eat my veg under the table! (The traitor-canine!)

    2. @Michael – “If you eat meat, fish, eggs, shellfish, and raw fat dairy if you can, you will never need a vegetable or fruit”

      And what your source of Vitamin C would be?

      1. Organ meat of grass fed animals, wild game, and marine mammals

        To be clear, I will occasionally eat fresh, ripe fruit in season from the trees that how in my yard or local area. And I sometimes eat the fruit vegetables like cucumber or tomatoes, but rarely and only in season from local sources.

        It is very easy for me to go months without fruit and weeks without vegetables.

        Vegetable matter is definitely of minimal importance in my diet and my biome is perfectly developed for my diet. As for MCT oil, butter and goat and sheep milk provide more that adequate amounts, with sheep cheese such as manchego and feta high sources. The actual percentage of MCT oil to other oils for a healthy diet is very small.

      1. Sondra I saw on your website you live in PT. I live in Olympia.

        1. Hey Michael!

          Lots of Primal peeps around here.

          Most of our raw vegan friends have succumbed to the lure of bone broth!


    3. @Michael:

      “Research comparing the gut microbiome of humans and other animals using 16S ribosomal RNA gene sequences provide some interesting insight into the diet our microbiome might be most accustomed, tuned our immune system, and kept our gut from leaking. When the gut microbiome of herbivores (e.g., sheep, cow, giraffe, gorilla, horse, rhinoceros), omnivores (e.g., ring-tailed lemurs, baboon, humans, chimpanzee, bonobo, spider monkey), and carnivores (e.g., polar bear, dog, hyena, lion) are compared, human samples not surprisingly cluster more closely with other omnivores. Interestingly, when compared to other hominids, humans cluster more closely with the bonobo diet. While bonobos do eat a small amount of leaves and meat, they are true frugivores, with a diet dominated by, as the name implies, fruit. Therefore, from the perspective of the microbiome, humans may be considered frugivores, although specialized, eating seeds and meat depending on availability. Flexibility is fundamental.
      Deeper shotgun prosequencing of the genes encoded by the trillions of bacteria in the gut across these same diverse mammals, reveal that the microbiome of carnivores are endowed with enzymes specialized to degrade proteins as an energy source, while the microbiomes of herbivores like sheep and gorillas are enriched with enzymes specialized to synthesize amino acid building blocks. Humans, in this case, are more like the gentle herbivores than the top-level carnivores we are often compared.”

      1. Interesting. I would need to break that information down to specific human populations with particular diets to have any use for me.

        Do populations eating a high amount of vegetable and fruit in their daily diet and that of their ancestors have the same biome composition as populations that eat primarily animals and rarely vegetables and have traditionally eaten this way for thousands of years? If a child is breast fed and then fed an animal based diet its entire life have a biome waiting patiently for the first piece of fruit?

        The critical point remains, the biome develops as a response to what we eat. And the evolutionary adaptions of bacteria is much faster that a human being. Biomes adapt quickly to changing human diets.

        A broad picture of what all humanity eats does not help an individual make a specific dietary decision regarding a particular food, especially something as unusual as eating raw tubers, unripened fruit, and potato starch.

        Choose the healthiest diet you can, pay careful attention to dietary effects, and your biome will adjust to meet your individual diet as it evolves. Do not make your dietary decisions based on some concept of keeping your colon bacteria happy.

        1. When it comes to the microbiome, yes children get it from their mothers. It differs between individual mothers/newborns, but it is still more specie-specific; eg one infant is closer to other human than let’s say to a lion newborn. If you don’t get antibiotics these initial bugs can stay there for a long time.

          (NPR: The Invisible Universe Of The Human Microbiome)

          If you eat a proper omnivorous diet, then your gut is dominated by bacteria from groups called Firmicutes and Bacterioides. Plant eaters tend to have both – but much more Firmicutes. Michael Pollan (“Eat food. Not too much. Mostly plants.”) has a gut with close to 60% Firmicutes inside, rest mostly bacterioides – with like few percent other. Omnivorous, but meat eating people can have like 60% bacterioides with like rest 35% firmicutes – but stil have both.

          When it comes to eating animals – they also have fiber-like substances in them, that are not digested, and pass to the gut to feed bacteria. These include parts like feathers, hair, but also collagen fibers. There’s a series on freetheanimal by Duck Dodgers about it. Notice these are extremaly rare in muscle meat – so if you only eat muscle meat you don’t get them.

          Your assertion that whatever you eat the microbiome adapts might be partially true – unfortunately we are only adapted to a few configurations. If you eat improperly, thus creating wrong configuration in your gut – it leads to a diesease.

          Examples of wrong configurations are here (Larry Smarr, Can we quantify our own ilness, look at about 9 minutes). Two diesease configuration are like: too much proteobacteria – ulcerative colitis, too few bacterioides – Crohns diesease.

          The advantage of RS-supplemented omnivorous diet it that it directs your gut into a safe configuration, thus avoiding dieseased ones.

        2. GTR, Thanks for all the information. At our regenerative medicine clinic we work with many people with differing manifestations of inflammatory response and all with some digestive issues. The more serious are those eating processed foods, vegans, and the Standard American Diet or some combination of the above.

          We place everyone regardless of symptoms on an animal based ketogenic diet, high in fat and moderate protein with minimal vegetable and no fruit. They all get well. All the autoimmune diseases, type 2 diabetes, metabolic syndrome, degenerative brain disease, obesity, IBS, are eliminated or improved significantly.

          Ultimately, their diet becomes an organic, pasture raised, local, in season diet. Their primary energy source is fat, adequate animal protein with limited local seasonal leafy greens and fibrous vegetables, usually fermented, and local fruit in season. This limit carbohydrate to less than 50 grams a day, with many days less. Some fruit in season days slightly more.

          No grains, bean, starch, vegetable oils, processed foods. To prove the safety of the ketogenic diet I experimented on myself for several years by staying in ketosis. I remained perfectly healthy the entire time.

          Of course, over the vast time of our evolutionary history, and with the billions of people alive today, there are many diets that we are able to survive on. I want to thrive, not survive. And so do our patients. The diet I presented here we feel is the best and has proved successful in every application. If you eat this way your biome will be perfectly able to handle all you can throw at it, provide all required immune and digestive abilities, and work with your brain and maintain a healthy hormonal system. There may be a role to play for FS as a transitionary supplement as people move to an animal based diet but once established they should be healthy without RS.

          Thanks for all your research and comments.

    4. Maybe we miss parts of the animal that we do not eat enough of today.
      Not only liver and organ meat, also parts of the skin and bones that we had to eat when we had less. The resistant starch is somewhere in there also for the carnivore animals , which means for us. We ate lots of berries and leaves of what we could get, some “vegetables” as paleo people too. I found when eating mainly aninmal fats, moderate protein and low carb that my blood pressure was not coming down. But is now incling down, with sauerkraut and raw potato fluor! Dandelion greens it could have been in the past, and can still be now.
      Wild garlic, leeks, onions. After all we are omnivores. Crocodiles and a few other species swallow their prey whole. They even digest the bones, with just a little more acidic stomach than ours at pH 1.5. Yes, dissolve the bones, and everything else!! I have no ideas of the colon of a a crocodile, but nature usually won’t waist much meanng that some useful fermentation is probably taking place also there before exit.

  45. Maybe its somewhere obvious but for some reason I can’t find it, what is the RS content of raw potato per 100g potato?

    I’m not afraid to chop up some raw tater in my Big ‘ol salad everyday so I would be glad to know approximately how much to add.

    1. Were you able to find this out? I too have been looking and can’t find it. I do the same things with my salads, and i actually enjoy the raw potatoes!

  46. I have a few questions please. What about the arsenic content of rice? I assume that resistant starch doesn’t feed the bad organisms as well as the good? What about konjac as a source of RS? I have seen a product called Slendier Organic Konjac Spaghetti in Ocado in the UK. This is pre-cooked, so how would that affect things? Parboiled rice has RS, but what about after it has been cooked? Do we have to then cool it? What about cooked & cooled tapioca? Is tapioca flour the same as tapioca starch? What about mung bean sprouts? Also, please be careful when cooling & reheating rice. Uncooked rice frequently contains bacteria called Bacillus cereus. These bacteria can form protective spores that survive the cooking process. If cooled slowly, these spores can germinate, grow and produce an emetic (vomit inducing) toxin. Reheating rice before serving will not inactivate the emetic toxin or kill all the bacterial cells, so the rice may not be safe.

    1. 1. I’ve been buying California rice because there is supposed to be less arsenic in the soil.

      2. The general idea is that the good bugs (if fed) have ways to inhibit the bad ones. For example, by releasing lactic acid which yeast don’t like.

      3. Konjac is a good prebiotic fiber but is not RS.

      4. Mung bean “sprouts” have used up the starch in the sprouting process. Mung bean starch has RS.

      Okay, that’s it for me…happy hunting for the other answers!

  47. Very dumb question, as a tag-on to my last very dumb question.

    Mark says “600 grams of baked, then cooled, potato has around 25 grams” of RS. Is that 600 grams as in 21 ounces, as in almost a pound and a half?

    That’s a whole lotta potato. That can’t be right, can it? Maybe the potato starch is the way to go after all.

  48. Going a little off topic here, but from reading Free the Animal’s RS posts, it seems there has been a shift in what we should be eating now. Up to fairly recently, it was leaning towards plenty of protein and fat, adding butter to veggies, bacon fat to potatoes all the time,etc but Richard Nikoley seems to be suggesting that fat is not particularly heathful and his latest guidelines have suggested easing up on the fat, especially with the now RS based meals we should be having. A general round up from Mark on our daily suggested menu would be good too.

  49. Super awesome info Mark! Thanks for following up the other article by answering all the questions it generated!

  50. Ok, still have a question or two. I’m assuming that, as with most things we care about, not all potato starches are created equal…

    When you say ‘raw PS’ do you mean it’s made from raw potatoes (never cooked) or do you simply mean don’t cook with it? Are some potato starches made raw, and some not?

    Is organic important?

    I’m not being lazy – I just spent 1hr+ trying to find out this info and my head is spinning.

    1. It’s all raw. Not that raw/cooked matters if the end product is what we want.

      I’d say that all potato starches are created equal, for all practical purposes, regardless of process. PS is not some new, suddenly arrived food. It’s been used in Asian cooking for many years.

    2. Lee–You are correct. You need to buy raw, unmodified potato starch. “Normal” potato starch or potato flour is not what you want–you will digest it into sugar, it will make your blood sugar zoom up, it will make you gain weight, it does not feed your gut biome in the same way. Raw unmodified potato starch is what you want. For example:

      1. Oh good, well that cleared THAT up! Ha ha. Best of three, anyone?
        Thanks for your replies 🙂

        PS – In Australia (where I am), apparently potato starch and flour are the same thing, just to confuse things some more. I have a bag of ‘Potato Flour (Starch)’. So, yay. But I can get some Bobs Red Mill stuff here so I’ll look out for that.

  51. Sorry but all this fiddling around everybody does ad infinitum makes my head hurt. I tolerate RS. I dump some in a glass of water. Stir with one of those little whisks, glug, stir, glug, stir, glug. Done. Now on with my life. If you don’t then make changes. I know some of you are fascinated by every tiny detail, but no offense I had to back off some and skip comments most of the time. I am old. Life is too short. Take a look around. I learned that.

    1. Kudos. I tried to say the same thing, above. Too much fretting, too many unGrok smoothies. Just chug it in water, and like you say, you’re done.

    2. I should have read this comment before posting my long whiny rant below… You’re right.

  52. Hello and thanks folks for the very informative answers. I’m a bit more clued in with regard to different types of starch and their benefits / detriments, as well as much more confident now about getting the flora as diverse (and therefore balanced) as possible. I just made some kefir and plan to use it in morning smoothies. Can I take this along with acidophilus capsules? Or should they not be mixed?

  53. Does it matter how long the rice & potatoes are left to cool for? Only I read somewhere else that said cooked & cooled for 24 hours. Is that right or can it be cooled for just a few hours?

  54. For someone with SIBO, will this help or hinder the problem of too much gut flora in the wrong place. I am usually desperate to starve the creatures, rather than feed….

  55. Thank you so much, Mark! This is amazing – and you even used my question in your post! I feel so special 🙂 I’m glad I can enjoy sushi and potato salad knowing that I’m feeding my gut bacteria.

  56. Hi everyone. Apologies if this question has been answered somewhere. I am wondering if it is okay to mix potato starch into a small amount of Kombucha instead of water or sparkling water, as Mark suggested. My concern is that the bacteria in the Kombucha would begin digesting the RS before it reached the colon where it is desired. Also, would either of these (potato starch or small amount of Kombucha) be considered breaking a morning fast? Thanks!

    1. My understanding is that combining kombucha and RS should be great for helping the probiotic bugs get through the stomach and SI to the colon. Richard nickoley and Tim steel at Free The Animal certainly recommend combining the two ie prebiotic and probiotic. I personally have mixed it with yoghurt. Cheers

  57. Prebiotic soup: 1 potato, 1 small celery root, lots of alliums (for inulin), some herbs, and enough gelatinous beef broth to make a thick soup. Chill for 24 serve and then warm gently before serving. My microbiota is happy.

  58. I don’t know why, but this topic is causing me stress and frustration. I just want to be able to eat food that makes me feel good and be done. So really, how important is this? Can I just get a bottom line here?

    I eat about 3-6 oz. of protein from meat and eggs, two pieces of fresh fruit, 3-6 servings of about 1/2 cup of veggies and drink a 6 oz cup of yogurt kefir almost every day. I eat sweet potatoes/yams and bananas 2- 3 times per week. Every other day I take a magnesium capsule, a b-12 capsule, a C-Q10 capsule, 1000 units of vitamin D and a big fish oil pill. Maybe once or twice month, I eat some rice or pasta, and once in a great while, I eat restaurant/junky fast food. Is this good enough??? I feel good, have energy, and am maintaining my weight. Are we done here? LOL 🙂

    I don’t want to come off as too harshly critical (I Love you Mark!) or annoying, but … the whole thing that attracted me to PB was the simplicity. For some reason, this RS stuff feels really complicated… sorry to whine :-/

    1. Your diet is certainly fine. Of course there are always improvements. Never eat grains except rice occasionally.

      There is absolutely no reason for you to add RS to your diet. RS should be treated as a supplement to be used only in certain situations for a particular individual when indicated. As medicine, not a nutritional component of a healthy diet.

      No need to stress.

        1. Thanks, I felt the same way too! I have been primal strict since January 1st (few cheats in between there.. literally only a few as I have a big goal in mind – 6 pack by my 30th birthday) and I love the simplicity of primal. This jacks me up in the head! But I will not stress about it, knowing that RS does not need to be added.

  59. so if cassava has resistant starch when cooked and cooled, I am assuming that the cassava cake I make (grated cassava, eggs, coconut, coconut milk and tapioca with a little honey) that is baked and then stored in the fridge would be feeding my gut flora – resistant starch from the cassava, inulin from the coconut :-). It tastes good too!

  60. I love sushi. All kinds. Of course not with the fake crab or anything tempura. But what is better than raw tuna or swordfish, mahi mahi even. Yum. I make it at home so I know exactly what is going in each roll. A word to the wise however, traditional sushi rice calls for cooking the rice in sugar water. Seems like a waste to me, but I suppose it has something to do with the “stickiness” that is desired. So before you go picking up pre-made rolls make sure to check the label, or better yet, make it yourself!

  61. I am concerned about eating raw tapioca starch after reading this – Cassava should never be eaten raw as the root composes small quantities of cyanogenic glycosides, especially hydroxycyanic acid. Cyanide compounds interfere with cellular metabolism by inhibiting the cytochrome-oxidase enzyme in the human body. Peeling followed by cooking ensures them safe for consumption by removing these compounds.

  62. I don’t understand what difference it makes for digestion whether you eat rice or baked potato, cold or hot?

  63. Green bananas don’t stay unripe for long
    (I am talking regular bananas, not plantain).

    If I chopped green unripe bananas and freezed them,
    and then took them out of the freezer and ate/blended them,
    what would their RS content be?
    Same, higher, lower than if I had had them “fresh”?


  64. hey..
    i am a bit confused.. i am doing carbbackloading and i have phases where i eat extreme high in carbs & super low in fat and then times where its the other way around.. during the low carb phase i would like to start eating some resistant starches, since from what i understood they wont raise my insulin and wont kick me out of the ketogenic state.. (am i correct?).. here is my question.. before i start implementing more starches into my diet i have to make sure i understand the differences between starch and flour since i have to make sure that i eat less than 20g of carbs during the ketogenic phase.. so what exactly is the difference? is there a starch of everything you can find as a flour? is tapioca flour and tapioca starch the same (someone mentioned it in a comment)? how do you extract the starch of the vegetables?

  65. So if 25g of the 30g carbs in a banana is RS, do you still count all the calories of the banana? or would it actually go from ~120cal to just 20cal??

    1. Wikipedia counts calories from resistant starch at half+ of normal, digested starch.

      “Natural resistant starch delivers between 2-3 kilocalories/gram (8-12 kilojoules/gram) versus 4 kilocalories/gram (16 kilojoules/gram).”

      Notice these won’t be in your carb budget, but more into fat budget, as the bacteria converts resistant starch to fats, so the energy is available to the organism as fat.

      1. Whoa wait, so RS is converted to fat? I thought RS just “passed thru you”, i.e. was not converted to energy. Wouldn’t that mean it is actually 9cal/g?

  66. My husband is having problems with kidney stones. Is there a natural way to help prevent them? Is there natural meds he can take to not get them? He has tried staying away from foods that may cause the them but no luck.

  67. Thank you so much for addressing my question and directing me to Dr BG’s! Her blog has pulled it all together for me (I’ve been reading it two days straight 🙂 and I have started implementing her advice. The interesting thing is that I haven’t tolerated PS or SBOs individually, but in combination they seem to treat me well!

    Eternally grateful for the link and this series! A messed up gut ain’t no joke, and having been there for 10 + years I am so looking forward to fixing it!

  68. In the process of heating/cooling, can you manipulate the temperature to increase the amount of RS created? i.e. Could freezing my rice be better than refrigerating it? What about length of time the food is cooled for? Will that affect the RS level?

  69. hey.. i have been using potatostarch and tapioka starch for the past days and i was wondering why does starch give you a feeling of satity even though you dont extract any energy from it?

  70. The big ‘LOOKOUT!’ with sushi (rice based sushi, like hand rolls etc.) is that the rice is sweetened with plain, ol’ sugar, as well as the vinegar. It’s the most basic recipe, and rarely varied. If in doubt, ask them what’s in the rice. If they pull out a bottle of sushi seasoning, it’s absolutely got sugar.
    I cannot go near any of this kind of Japanese food for that reason- it sets me off on a bender, my hunger signals and cravings get totally messed up. It only took a minute of investigation to find out why…

  71. What about those of us who want to be in mega fat-burning mode? Should this be something we generally avoid still, like potatoes? I am in “I wanna be hot and ripped” mode – currently less than 60 carbs a day, usually end up around 40. F/P/C ratio is generally 60/25/15. Working out 6 days a week (mostly weight training, yoga, and light cardio, maybe once a week I’ll do the equivalent of sprinting for cardio). Because I have IBS and sometimes other digestive issues, I became curious about this. I just tried this out and had some sushi for lunch. I am not sure how many carbs to count for the day, and again, if I should avoid in general right now?

    1. I wondered the same thing. I found their customer care said it is “unmodified” by virtue of the fact that it is organic. However, they also stated that the product is heated when cooked and dried.

  72. Just wondering why reheating a previously cooked potato preserves the RS but heating unmodified potato starch destroys it? Isn’t the potato starch an extract from the potato and therefore the same substance?

    1. Chris – Without getting into the science, reheating previously cooked potato or not, modify the starch and nulls it RS properties. The starch is beneficial only when cold. So next time, cook your potato, let it cool completely and incorporate it into an egg salad. You can also peel a small potato and eat it raw, or grate it, squeeze it’s juices over a bowl and drink the starch (add the grated potato to a green salad). And if on occasion you decide to cook it with eggs, I don’t think that the sky will come crashing down; remember the 80/20 (or 90/10) rule?

  73. This is great stuff…. when first diagnosed with diabetes, I was sent to a nutritionist who highly chastised me when I said I would just stay away from grains (she said if I had to avoid a whole food group to reduce my blood sugar, something else was wrong…LOL…. whoooo-boy… don’t we know it!!!!) Meanwhile, intuitively (my sister &) I have eaten raw potatoes since childhood as a crunchy snack. People think I’m weird & how could I do that, but they’re appealing to me. Also, I detest bananas that don’t have some green on them (as far down the stem & into the body of the skin as I can find)…. Nix on the freckly ones…. jeez, if we’d only LISTEN to our bodies we wouldn’t be in these fixes…. I’d like to give a tip of the hat to Dr D’Adamo, who my nephew studied with at Bastyr years ago….he proposed that blood type & diet had a correlation. Being a type 0 (the oldest blood type–hence PALEO), I can see where the grains just don’t fit in. My nephew (also a naturopath) forsook the wheat grains long ago…
    Anyway, it is nice to know I am not psycho in intuitive beliefs and that more and more studies are showing that eating THIS way works (PS….just following a very loose paleo diet for 4-5 days, my fasting BG dropped 30-40 points). Take that, mainstream nutritionist!!!

  74. BLOOD SUGARS are up
    I started with a little potato starch- however my hand pain flared up (nightshade sensitivity). So now I’m buying green plantain, pureeing them with a bit of cinnamon and a drop of vanilla stevia and drying into crackers.
    Certainly there was ‘fartage’ as I increased the dose- my issue however is that my blood glucose levels are spiking soon after- and the RS intake has not blunted my glucose response to other carbs as fat as I can tell. Have also gained some weight over this past 2 or 3 weeks of trialling cold potato and cold legumes.
    I just ate around 2 Tbs of plantain cracker after a coleslaw and avocado and mayo lunch and my reading is around 130. I’m suspecting it comes down to the amylase gene issue- I shall revisit my 23andme to see what comes up there.

  75. Hi sir i am pradeep. I am 27 years old but my weight is 57. I am looking very slim. I want to increase my body weight. If i increase my weight can i have plantain banana daily. Pls i want your advice.

  76. So, when you cook rice, should you drain it and wash the excess starch off of the rice with water before cooling it? Or do you drain it without rinsing the excess starch off and then cool it?

  77. I’m confused about something that seems contradictory in this otherwise very helpful post…it is mentioned that potato starch is not RS, but then later it is:

    “I don’t think it works like that. For retrograde RS to form, it has to be in its whole form – potatoes, not potato starch; cassava, not tapioca starch; rice, not rice flour.”

    “Aside from smoothies, sparkling water is the best vehicle I’ve found for potato starch. The bubbles seem to enhance the dispersal of potato starch granules into the medium, even without a blender. Just a fork or even a quick stir with your index finger is enough to get it completely mixed in.”

    Thanks very much for your feedback!

    Read more:

  78. So are you saying that only cooled potatoes have resistant starch? In other words you can only eat, say potato salad and thats it???? I can find no other use for cold potatoes.

  79. This is the answer I was looking for, thanks so much:

    “It’s not a resistant starch per se, but rather a prebiotic fermentable fiber. Studies indicate that while its consumption does improve constipation and increase production of the short chain fatty acids (SCFAs) propionate and acetate, it does not increase production of the most beneficial SCFA, butyrate.”

    I was wondering if resistant starch was some kind of code name for oligosaccharides which cause me infinite agony and I’ve been on the low FODMAP diet for years because of it. I’ve noticed that some websites suggest different probiotic supplements called “soil based probiotics.” I was honestly thinking I’d have to buy some peat and find a palatable way to accidentally on purpose contaminate my food with it. Glad to have another option. 😉 I WILL GET WELL even if I have to eat dirt.

  80. Hi Mark,

    Here’s my challenge. I’ve been eating primal 80-85% of the time for the past year and half… I’ve lost quite a lot of weight and now am focusing on buidling some lean muscle.

    Unfortunately, I haven’t gained much after 6 months of light to moderate lifting (3-4 days a week). I look skinner than before and this is alarming for most of the people (friends, family, and colleagues).

    I hate listening to my coach who advises me to eat brown rice or some carb in each of my meals. I love the primal way, but I think I’m missing something. (I do binge eat on Fridays—heavy lunch, evening beer… and this spills over on Saturdays as well. But I’m back to the basics on Sunday and onwards.)

    Can you suggest me a solution here?


  81. Anyone know what it is about the chemical structure of RS that makes it “resistant”. what changes about the starch when it is heated and cooled. this is all very mysterious to me. I have a background in science and a masters in Physiology. Please don’t make me go searching Pubmed if one of you knows the deal with this ahah. Thanks!

  82. I’m a full blown diabetic 2. It’s ok to mix potato starch with eggs or coating for fish/chicken,fry,cool,eat? It won’t cause my BS to increase?

  83. Re Quest Bars. I don’t know how they work for others, but they raise my blood sugar as quickly and as high as if they were sweetened with sugar (confirmed by blood testing on numerous occasions). Don’t assume the marketing claims are true, at least not for everyone.

  84. hi
    so just one question to make sure i create a good amount of RS say in potatoes should i i bake them WHOLE and cool them in fridge for one day and then cut them thinly to make crunchy crisps in oven next day or should i cut them before cooling them previous day?
    2) second question i dint use oil or fat when i bake them i just let them crisp but can i put oven on medium- high heat next day or will that recreate the starch?
    do i have to cool them again before eating the crisped potatoes i cooked in oven??
    thanks [lse let me know asap

  85. That was my point: Why not eat little purple potatoes raw? RS and anthocyanins.

  86. Does taking digestive enzymes cancel out the effects of resistant starch? Doesn’t it then get digested? Sorry if someone already asked this question.

  87. Plz help. When you say raw potato starch is it raw when you buy it? I just got some from holland and Barretts and am going to put it in water to drink but I don’t know if it’s raw or not? Do you mean raw as in not cooked by me?

  88. I’ve read that RS3 forms when starch is cooked then cooled and the water is forced out, which is why when reheated it forms even more resistant starch because more water is forced out. But what about if you make soup with potatoes and put it in the fridge? Will it still form RS3 since it’s sitting in water?

  89. If you check assorted site and articles — there are different amount of fiber in whatever is listed. For instance my frozen peas says there are — in 1cup of peas — 5 grams of fiber. Is that how much resistance starch is in the peas or?

    If not how do you figure it out…

    Thanks, April

  90. Many of the statements here are contradictory and not supported by the research, such as the statements about room temperature rice (in sushi) negating the RS content followed almost immediately by statements regarding the conserved RS content of reheated starches.

  91. Please clear this up for me. Someone on page 1 asked about cold pizza crust make from tapioca flour, etc. The answer was, “I don’t think it works like that. For retrograde RS to form, it has to be in its whole form – potatoes, not potato starch; cassava, not tapioca starch; rice, not rice flour.”

    So — the references that say that cooked/cooled pasta made from potatoes or rice (presumably from potato or rice flour — generally brown rice flour) have a good amount of RS — are incorrect? Type 2 RS is destroyed with heat and neither that nor the remaining starch will form retrograded Type 3 RS when cooled? Related question — this also means that gravies or other things thickened with unmodified potato starch (heated = RS gone) won’t form any retrograded Type 3 starch when cooled?

  92. …continued from previous post. So — even all the great paleo breads I’ve been baking using cassava flour, tapioca flour, coconut flour, unmodified potato starch, even almond and cashew flour — no significant RS after baking and then refrigerating the bread?

  93. Hi Mark,
    Can you make a green banana smoothie with your morning glass of kefir. Will it lessen the nutrient value of the Kefir or the resistant starch? Many thanks. Max

  94. The potatoes (white, red, sweet, whatever) have to be boiled and the cooled in the refrigerator several hours to become resistant starch-same with rice (preferably brown rice-cooked then cooled in frig several hours.)The potatoes are delicious in cold potato salad, cold potato soup, cold mashed potatoes (can slightly heat), and rice is great in salads, and rice pudding (my favorite.) The raw potato starch is great in different smoothies, add to potato salad or rice pudding, in yogurt, in cereal, is good mixed with sparkling water and some lemon or lime juice. I make a morning breakfast drink of liquid of choice (unsweetened almond milk, regular 2% milk, protein drink, apple juice,and water), some kelp, plant based greens, spirulina flakes, chia seeds (presoaked), green banana (cut up & frozen), walnuts &/or almonds (presoaked), and other fruit if I have it, Drink water during the day. I am increasing amount of raw potato starch slowly each day. It sure lasts a good part of morning and gives me energy and most important balances my blood sugar. At night I have a green banana with almond butter or peanut butter-sleep great. I am not an expert but I use this everyday. Just passing on what I learned and practice. In the morning it helps you with your sugar to do some easy exercises to warm up your muscles (I do them before I get out of bed if I can) -some great ones on youtube for diabetics- to help work the glucose levels. Hope it helps someone 🙂

  95. I’m really curious about the safety of eating cold rice in particular. I used to save my leftover white rice when I got Chinese food and ate it cold topped with eggs for a few days after until it was gone. Then I read about Bacillus cereus and how you should refrigerate rice ASAP and reheat it thoroughly the next day only, and then toss out any remaining leftovers or risk food poisoning. Because I have a medical condition that makes food poisoning especially dangerous for me, I have avoided my old breakfast treat. I love the concept of resistant starch, and while I know there are other options to get it, I would like to know if there is a safe way to eat cold rice without putting yourself at risk of food poisoning. Is there a special way to cook it that kills the bacteria? I’d be happy to hear from anyone who knows.

  96. Great info. Thanks. I wonder about RS in YUCCA ROOT. It’s a staple in S. America & available in U.S. markets. Boils just like potato & tastes very similar — can be eaten in all the same ways. It may have more fiber & nutrients than white potato. Any info on RS & how it might feed good bacteria?

  97. If I freeze potato chips will they be transformed into a health food?

  98. Will potato starch lose its starch resistant properties if cooked? (say added to a soup)

    1. Yes, if it is chilled the resistant starch will reform but heated it is plain ole starch

      1. That isn’t true, reheating shouldn’t change most resistant starch and will actually form a third type of resistant starch and foods like white rice will continue to increase their IR content with repeated heating and cooling cycles. Reheating is perfectly fine.

  99. I am pretty sure you endorse the use of Potato Starch (like Bob’s Red Mill) but one of your answer was this

    I don’t think it works like that. For retrograde RS to form, it has to be in its whole form – potatoes, not potato starch; cassava, not tapioca starch; rice, not rice flour.

    Just wanted to get some clarification, is potato starch a good way to incorporate RS into the diet?


  100. Everything I can find in green bananas is about eating them RAW. My husband is Latino and they use green bananas and plantains the way we use potatoes. I have used them in place of potatoes in pot roast and stew many times thinking they’d be significantly lower in digestible carbohydrate. I’m less interested in an RS source than I am reducing available carbs. Does anyone KNOW the available carb content of COOKED green bananas or plantains?

    Once cooked, do the converted starches convert back to RS when cooled?

    Thank you.

      1. I read it for you and on page 194 it says the amounts.
        Per 100g of RIPE raw plantains, it had 11.4g of RS.
        For boiled UNRIPE plantains it had 1.6g of RS.
        So basically, heating the plantain destroys almost all of the RS.
        So unfortunately, you’re going to have to eat those suckers raw to get the RS.
        I don’t know if cooling helps bring some RS back, but I doubt it since scientific data only mentions potatoes & rice for that.

  101. I just started trying resistant starch in the way of cooked and cooled roasted potatoes. They are amazingly yummy in a salad, kind of like croutons. So far my bloating has actually decreased and my cravings have been majorly curbed. I had a lot of questions and this article has been extremely helpful in answering all of them–Thanks!

  102. If I add potato starch to hot cocoa or hot chocolate will the resistant starch be destroyed or maintained?

  103. So I am trying to the potato hack diet to with intermittent fasting to lose some weight for a competition. I also have issues with my stomach. Would mixing thrice cooled and heated potatos with 24 hour incubated plain whole milk yogurt help reset my stomach and stay true to the whole food fasting?

  104. Can you list the required RS foods , how much is a serving and the number of RS grams for each. Thank you.

  105. Which brand of potato Starch is a resistant starch? There are several online bloggers claiming 1TBS of Bob’s Red Mill potato Starch has 8g RS per tbs! However, their nutrition panel says differently so I e-mailed Bob’s Red Mill about their unmodified Potato Starch and they replied that it is NOT a resistant starch.

  106. If making bean soup do you have to cook the beans seperate then cooled and then add the beans into the rest of the soup receipe or can you cook all at once let cool for 24 hours then heat and eat?

  107. Hey Mark, as regards the formation of the SCFA Butyric Acid (Butyrate) in the gut, one way, as you point out, to increase it is to up intake of resistant starches. But isn’t Butyrate also found directly in some foods in small amounts with the best source being butter from grass fed cows? So what if we added, for instance, potato starch to kefir or yogurt and let it ferment. Would that as does butter provide a good source of edible Butyrate?

  108. Hi! I was wondering if resistant starch is possible with avocado or olive oil kettle chips that are store bought only consisting of 3 ingredients the mentioned oils potatoes and sea salt?

  109. Is resistant starch 4!
    as effective as “natural” resistant starch,and if so ie “carbs nada” how many net carbs are there?

  110. Will using Bob’s Red Mill Potato Starch dissolved in water work as RS?

  111. I am trying to figure out why people keep recommending potato starch but not potato flour when it comes to RS. If potatoes that are cooked and then cooled have high RS, and potato flour is also made by cooked and then cooled potatoes, wouldn’t they both have the same RS? Thanks!

  112. After juicing lemons, I peel of the skin and freeze for later use in cooking. The pith halves left behind I store in the fridge and normally eat one a day. I think this is a good and fairly palatable source of resistant starch?

  113. Does anyone know if the RS in very green bananas is also converted to sugar when cooked similarly to cooking potatoes? And, if so, does the retrograde cooling period also work with cooked green bananas to restore the RS?

  114. Sparkling water is a good vehicle for potato starch,but fulvic water is even better.