3 Sections:
1. Potatoes and PS
2. Other RS sources
3. Probiotics


Q.  Would soaking the potato in water remove the resistant starch?
A.  No.  Soaking in water doesn't remove much starch, you'll see the starch at the bottom of the bowl. Pour the water off and lick it up!  
Q.  How can I make my own potato starch?
A.  Potato starch is very easy to make...just shred and pulse the shreds in a blender, then squeeze through cheese cloth (you'll have to add some water to the blender). Squeeze it all into a bowl, let it settle to the bottom. Pour off the water and scrape the wet starch onto a plastic paper plate. Leave the plate on the counter overnight and in the morning you'll have a plate with a big chunk of nearly pure potato starch. Crumble this up and use it how you like. It will have a brownish color because you didn't add an antioxidant like they do at the starch factory. You should be easily able to get 4TBS from a pound of potatoes.
Q. Do the carbs in resistant starch count as part of my daily carb intake. In other words if I am trying to stay at 90g of carbs a day and I am taking in 40g of carbs from the resistant starch, does that mean I have 50g left or are those carbs in a different category because they are processed differently?

A. No, they don’t really count. You’ve still got 90 grams left.  If you wanted to get technical, you could count RS calories as ½ fat as your gut bugs turn RS into several kinds of fat.
Q. Does anyone know if RS has any affect on blood pressure?
A. RS shouldn’t have any effect on blood pressure directly, but it does have an effect on gut and whole body inflammation, which can have a favorable effect on BP. So, fix the gut and metabolic syndrome markers, reduce inflammation and hopefully BP normalizes.                 
Q.  Bob’s Red Mill says they make potato starch from cooked potatoes, how can that be?
A.  No, they are not cooked.  Most, if not all, starch processes begin by blasting the potatoes with hot water or steam to peel and clean them.  This does not cook them.  If they were truly cooked, there would be no resistant starch.  Potato flour is made from cooked potatoes. I think sometimes they say the potatoes are 'cooked' just so it seems safer to the consumer, but they are not cooked in the sense that the starch granules are heated above 140 degrees.
Q.  How can you tell if it’s raw potato starch?
A.  A quick way is to mix it into a glass of water.  If it’s raw starch, it will quickly settle to the bottom of the glass and form a cement-like solid.  If it’s flour (cooked starch) it will just clump up and turn dough-like.
Q. How much RS is in sliced potatoes in dehydrator (potato chips)?
A. Same as raw. A raw potato that weighs 200g has about 30g of RS. If you dehydrate it, it will still have 30g. Fried potato chips will have significantly less. Just make sure to keep temp below 140 deg F.
Q. Do you think 1 tsp bid (twice daily) of potato starch is enough?  
A. 1tsp is about 2.5g of RS, slightly less than the national average intake of RS.  This little bit won’t do much for you.  1tsp twice daily is a good starting dose, increase it bit by bit over weeks and see how you do. I think it is going to turn out that the 'proper' dose is 10-20g of RS2 (raw starch) plus 10-20g of RS3 (cooked/cooled starch) per day. Just a hunch, but that is pretty much what I aim for.  Alternatively, just get your RS from real food and skip the potato starch altogether.
Q.  (From Tatertot’s Mom) Dad & I have a difference of opinion on "cold potatoes."   One of us thinks it's raw potatoes,  the other thinks it's cooked and chilled potatoes. Are either of us right?
A. It's really strange, but the way this works is that if you cook a  potato, then cool it down, it forms the resistant starch we talk about.  You can actually heat it back up and even more RS forms.  It works the same with rice and beans, too. The traditional way of preparing lots of food created RS.  The way we eat today, doesn't.  Back in the old, old days, they would cook potatoes or yams, roots, whatever, by laying them in or next to a big fire.  Then they'd eat those foods for days after the fire went out.  Same as beans, think how Mexicans made big pots of beans, let them cool, and then made refried beans.  Rice was always eaten the same way, make huge batches, let it cool and eat it for days either cold or reheated. RAW potatoes are also a good source of RS—actually the very best source in the world.
Here's a breakdown on what happens to RS in a regular, tennis-ball sized, potato:
Raw - contains about 30g of RS
Cooked - 1g
Cooked and cooled - 3g
Cooked, cooled, reheated - 5g
Cooked, cooled, reheated, re-cooled - 6g
It will keep gaining RS with each heating/cooling cycle, but never as much as in the first cycle, if that makes sense.
Q.  For those who have been consuming PS for at least several months, have you seen any effects on weight/body composition that you can attribute to the PS?
A.  I can attest to the fact that it has made maintaining my weight effortless. I’ve seen a few reports that people have lost weight easily while consuming RS. The Perfect Health Diet has a weight loss version that is high in RS that people rave about.
Q.  I have been baking potatoes and chilling them, with some butter, and with the skin on......is it ok to eat the skin? I love the skin.  I will bake a large potato, chop up and mix with butter, chill in fridge for a while, eat half one day and half the next day.
A. The skin is fine. The chilling effect needs to last quite a while, like at least 8 hours. But, don't sweat it. You have a good routine. If you wanted to tweak it a bit, cook 5 or 6 potatoes and store them in the fridge til you're ready to eat. They can be reheated and the RS remains.
What I like to do is heat up well-chilled potatoes in the microwave until just 'fairly warm', then mix a spoonful of potato starch in with some sour cream and put that on the potato. This makes a potato that would normally contain 'maybe' 1g of RS eaten freshly cooked, have closer to 10g of RS. That's huge for such a small tweak.                                 
Q. Could you please tell me what amount of potato and/ or sweet potato would equate to 1 tablespoon of PS or RS? My sister doesn't want to take the PS but wants to get the health benefits of RS. I guess they would need to be chilled for at least 8 hours.
A.  Sweet potato has too little RS to even consider, but they are healthy in other ways.  
With regular potatoes, if you were to eat 250g per day (roughly 1/2 pound--or an average sized potato) that was cooked, cooled overnight or longer in the fridge, then reheated by microwaving or re-frying/re-baking. It would have roughly 10g of RS, or a little under 2 TBS.
With the chilling, the RS starts to form at about 50 degrees and maximizes at 10 degrees. It's also time dependant, 8 hours is probably the minimum time for some RS to form. So colder, longer for better results.  Potatoes don't freeze well, they turn mushy when you thaw them, but rice and beans freeze well. Rice, beans, and potatoes all have about 15g per cup if eaten cooked, cooled, and reheated. An easy way to implement this is to simply prepare big batches and store in the fridge or freezer until ready to eat.


Q.  What about RS in soaked, cooked and cooked quinoa, buckwheat or rolled oats?
Also, there are a lot of snack foods that use sprouted lentils, chia, beans . Would those be a decent source of RS 3?
A. Sprouted, definitely very little RS.  The other things you mentioned all have some, but just a little bit. The RS is not really going to be a major reason to eat them, but it's a bonus if you like them and eat them anyway.  Probably the things I would say to eat 'just for' the RS would be:
- Green bananas
- Dried Plantains
- Cooked, cooled, reheated potatoes/rice/beans
- Mung Bean Noodles
- Raw Potato Starch
- Raw banana flour
- A slice or two of raw potato
Q. What is the difference between raw yams, sweet potatoes, and potatoes in RS content?
A. If you weigh a raw potato (regular white potato), 15-20% of that weight is raw starch. Of that, 75% of it is RS. With me? So if you weighed out 100g of raw potato, it would contain 20g of starch, and about 15g of RS.
A sweet potato has roughly the same amount of starch, but this starch is only about 5% RS, so 100g of raw sweet potato only yields 1g of RS. Sweet potato starch is more sugar-like than white potato starch, and is useful in the biofuel industry, the same as corn starch.
Yams are a bit of a mystery. There are so many types and cultivars. True yams are nothing like sweet potatoes or white potatoes. My gut feeling is that they contain quite a bit of RS, but how much, I have no idea. The ones we buy around here in the supermarket may be bred for higher sugar content, but I am just speculating on that. The Hadza people of Africa still dig and eat the same yams that were eaten by our ancient ancestral forefathers. They lay them next to a fire to char and soften them and eat them with the insides still raw and hard, in that manner, I can see them being a great source of RS. I think a lot of times what we think of 'yams' are actually sweet potatoes.
I know this is probably more than you were wanting to know, but hey, I wasn't so sure, either...
Bottom line: Potato Starch = 64% RS by weight. Sweet Potato Starch = 5% RS by weight. Yam Starch = 10-20% RS by weight. Hope that helps!
Q. Can I freeze green bananas, potatoes, or raw starch?
A. Freezing has no effect on raw starch granules, as found in potato starch or green bananas. The only thing with bananas, they will be quite soggy when thawed, but for use in smoothies they will be fine.
The reason I can say this so confidently is because when they measure the RS in green bananas, they freeze dry it first, and the RS stays intact. The starch granules themselves actually are a form of antifreeze for the plant, remaining quite stable down to as low as -35.
There is a South American food, chuno, made by repeatedly freezing and thawing potatoes until all that is left is the starch.
Freeze away!
Q. How much RS if all I eat is rice?
A.  Cooked and cooled rice has about 5% RS by cooked weight. If you eat, say, 500g per day (about a pound) you'd be getting roughly 25g of RS -- 10X the national average. Hot, fresh cooked rice contains 0-1g, so you do the math there.
I never eat fresh cooked rice any more, I always get the Uncle Ben's Original Converted kind, cook it, freeze it, thaw, then stir-frying in a tiny bit of hot oil. The latter method really brings out the RS as it has a drying function, and results in rice that is roughly 15% RS.
Q. Do Tiger Nuts provide as much rs as raw potatoes?

A. I'd say the Tiger Nuts, as purchased in a bag, don't provide much RS at all, lots of other good fiber though, and too expensive to eat as a staple. As a snack? Par Excellence!
If you grew your own Tiger Nuts and ate them fresh from the ground, probably similar RS to a raw potato.                                 
Q. What about corn? Anyone know? I read Hi-Maize has RS, but is that in organic corn products?  My 2 favorites were organic popcorn & org blue corn chips! I have given both up BUT could add them once in a while, for the RS (and because I miss popcorn popped in CO & lathered w grass fed butter.)
A.  Hi-Maize is good for RS. 50% by weight and you can bake with it according to the makers. Sold as King Arthur Hi-Maize, not organic, however. Regular corn starch contains almost zero RS.  Corn itself, as in sweet corn, taco shells, or popcorn, contains a bit of RS, close to that found in rice, or roughly 5% by weight of food eaten.                                
Q. What are the diff between using banana flour & ps?  Is there anything to look for with banana flour?
A. The big diff is RS content—30-40% for Banana Flour, 70-80% for PS. PS also mixes really well with everything, BF nor so great.  Nothing really special to look for when buying banana flour, I think it’s all about the same.
Q. I was wondering if there is any significant RS to be found in rice noodles with ingredients including only rice flour and water?
A. For noodles, the highest RS is found in those made of mung bean starch, often called glass noodles.  In the rice noodles, some RS, maybe just 2-3%. Mung Beans noodles are like 20% by dry weight.                                 
Q.  I sliced a green plantain yesterday and left in the oven (warmed oven for 10m then turned it off). I ate some last night but figured the RS increases w time, is that true?
I bought a green banana too, although have no idea what to do w that!
A. For the plantains, here's what I do: Buy the greenest ones you can find, no black or yellow (maybe little black spots OK). Cut the ends off, cut them in half longways, then peel. Now lay each half on a cutting board and slice longways into 4-6 long pieces. Lay these on a screen of some type, I have one made of 1/4" stainless steel mesh, you want air to be able to circulate all around them. When they are first cut is when you want to salt or spice them, otherwise nothing sticks when they are dried.
Put the whole thing in the hot sun or a warm place and if you have a fan, point a fan at them. The drier the air (low humidity) the faster they dry. Paleophil puts his in the refrigerator to dry, I usually make too many at once for that.
Air drying them like this will result in bone dry, very white plantains. They have almost no taste but remind me of saltine crackers. I put meat, cheese, almond butter, pate, or whatever on them and eat them as snack or with meals, and usually munch a slice plain while driving to work. A large plantain has roughly 30-40g of RS, so if you make 4 slices, each one is 10g or so. These are considered RS2, the raw starch.
With green bananas, I just eat them. Peel them the same as I described above and choke them down while drinking a cup of coffee, they are not that bad and really good for you. You could also blend into a smoothy.
Q. Is freezing bananas ok as far as RS?
A. Freezing won't decrease the RS in raw bananas.
Q.  Banana and plantain flours contain a lot of potassium. Is the potassium in 4 tbs/day too high of a dose of the mineral?
A.  Would 1/2 a banana or plantain be too much? If you have been told specifically to avoid potassium, count it and regulate, but otherwise, 4TBS of plantain flour is like half a plantain.
Q.  I wonder why canned beans, which presumably are cooked using essentially the same methods used to cook beans at home (i.e., soaking and heating), contain such low amounts of RS. Can you increase the RS of canned beans by refrigerating or freezing them? I have tried several times in my life to prepare beans from scratch–never successfully. (They came out underdone, overdone, or with burst skins.)
A. It’s not so much the RS content of canned beans as it is the ‘traditional preparation’ aspect of a long soak which ferments the raw beans with Lactobacillus. Commercial canned beans are picked, cooked, canned. No fermenting. Yes, you could increase RS of canned beans by cooling/freezing. There is no real reason to never, ever eat a canned bean. It’s just that it’s so easy to soak, boil, and freeze small batches that I see no reason to go the canned route. I had never been good with beans until a few months ago. Now they turn out perfect every time. Experiment with types and cooking times, but just to recap. Soak over night or up to 48 hours, rinse, bring to boil, boil 10 minutes, turn down heat and simmer until tender. Easy Peasy.
Q. Is there much resistant starch in hummus?
A. About 5-10g per cup. Eat up!
Q.  What about Mung Bean Starch Noodles, AKA “Glass Noodles”?
A.  Mung bean starch noodles are a great source of RS, like 20g per 100g of dried weight. The ones I buy come in an 8oz package with 4 'bundles' of the noodles inside, 1 bundle is about 1 serving and weighs 2oz or 56g, which would supply about 10g of RS.  All I do to them is soak in warm water about 20 minutes and toss in a stir fry for about 30 seconds. if you try to cook with them they turn into a pastey mess. Mung beans seem to have a feature that makes them produce retrograded RS (RS3) very efficiently. I'm told there are also mung bean paste sheets that are equally delicious. I wouldn't worry about anti-nutrients of the mung bean being in the starch, from what I seem, anti-nutrients are associated with the proteins that are removed during starch production.         


Q. What’s the best way to start taking probiotics?
A.Take a very small amount of PS, like 1tsp, for now. Get some good probiotics that contain bifido, lacto, and even Saccharomyces boulardii. These are cheap. Also, buy some AOR Probiotic-3 sold by iHerb, or the one sold by Mark Sisson called Primal Flora or something similar with the same type of probiotics listed.
When you get these probiotics, take them every day, just once a day no matter what it says on the package. And start increasing the PS by 1tsp a week, if you start getting gas, just back off a little or work through it—gas isn't a bad thing.
The PS will lay the foundation for the probiotics to thrive and will help create a gut environment sustainable for them in the future. If this all works out for you and helps your rosacea, keep on with the PS and probiotics, but learn to get both from real food, ie. cooked and cooled stuff, and fermented veggies. You have the rest of your life to tweak it. Use PS as supplement not primary source once you feel you have healed your gut.
Don't skimp on the probiotics! They are just as important as the prebiotic PS.
Q. There are numerous references to PS’s ability to stabilize blood glucose (the anecdotes I read all tout BG lowering effects), but what if your BG is completely normal? Has anyone heard of it having adverse effects on healthy BG levels? How about on normal to low blood pressure.
A.  It doesn’t just lower blood sugar, it makes your body more insulin sensitive (IS), which in turn lowers high blood sugar. If you are already IS, you will just remain IS. Same with blood pressure. If high blood pressure is from poor gut function, fixing that should have knock-down effect on high BP, but won’t just outright lower already low BP.
Q. Do I have the right gut bugs to eat RS?
A.  I think that the missing piece to all this is solved by using RS to create an environment where known probiotics thrive and stick around. Eating probiotic foods and supplements with an inflamed, dyspeptic gut does not encourage them to stick around.
Even the earliest studies on RS showed that it lowered the intestinal pH, increased butyrate, and created an environment suitable for lactic acid producing bacteria and the entire bifido clan. The lowering of pH is gut bug moderated and creates a self-fulfilling environment. While not every single person may have the right gut bugs to see immediate results, it does seem that most people have suitable numbers of RS degraders so that RS + probiotic supplements can quickly restore balance that has a lasting effect.
Without RS (and/or other suitable fermentable fiber) the intestinal pH will be higher, butyrate production lower, and create an environment more suitable for pathogens and their biofilms, leading to a decrease in colonocyte health, more inflammation, less immune system regulation, and other downstream effects of the gut-brain connection.
Q. I see that AOR Probiotic-3 has the Potato Starch already in it. So, do you recommend the AOR 3 alone at first or adding additional PS?
A. I like to take the AOR 3 at same time as PS, but yes, they come with their own. Amazing, huh? There is actually an entire class of pharmaceutical grade potato starch on the market. Also, what I's recommend, take 1 a day for a week or so, then maybe 2 a day for a week, then back off and just take like 1 every 3-4 days. They will last a lot longer that way and I think just exposing your body to them periodically while also taking in lots of RS is perfect. Nobody really knows what the SBOs do inside you, but it seems they trigger an immune response that trains your immune system to respond appropriately to real dangers. Kind of like why babies put everything in their mouth. I think it's called "oral tolerance" in the science books.
People with immune deficiency problems are not supposed to take the SBOs, like people with advanced HIV or on immune suppressing drugs.
Q.  Can you point me in the direction of any information regarding RS supplementation pre- and post-bariatric surgery? Or, even your own thoughts on the subject…
A.  What I write here will be the first thing ever written on the subject… How does that make you feel?
Lots of studies suggest the quick relief from diabetes and subsequent weight loss following bariatric surgery has a lot to do with gut bugs. I believe it.  My thoughts are that one should try to get as healthy of guts as possible before and then again after. After the surgery, you’ll be reeling from antibiotics I suppose, so it’s doubly important to get things back on track.
If I could give advice, it would be for afterwards to start taking 1TBS of potato starch, 1TBS of banana flour and some very good probiotics containing lacto and bifido strains. Not sure if you want to take the soil-based organism probiotics right away, but as soon as you are back to normal and eating your new regular diet, maybe a week after the surgery as long as you aren’t immune compromised in any way.
Don’t take any other fiber supplements, they will swell and could cause you problems.
Just my ideas. Hope it helps. But after any surgery, you need lots of care to get gut bugs back in shape.
Q.  What probiotics do you recommend, and why?
A.  Although availability and price may be a challenge, we recommend:
  1. Prescript-Assist
  2. AOR Probiotic-3
  3. Primal Defense Ultra
  4. Primal Flora

These four blends have the microbes most commonly missing from our lives, the soil-based organisms and other equally important microbes such as lactobacillus and bifidobacteria species.  All of these blends have been thoroughly vetted through third-party testing laboratories for safety, contents, and contaminates.
Q. All this talk about “soil-based organisms,” can I just eat dirt?
A. Our ancestors certainly ate lots of dirt!  We don’t recommend eating dirt for several reasons:  pollution and pathogens.  If you grow your own vegetables, and use no chemicals, then it is perfectly fine to eat minimally washed vegetables plucked straight from the ground.  Plants roots are much like our intestines and attract their own bacteria, these root bacteria keep pathogens away so the dirt clinging to roots is much safer than a shovel full of random dirt.
Q. Any theories on why farting subsides after a couple of weeks on RS? I went from farting constantly on 1 tbsp a day to barely farting on 5 tbsp in that time.  Someone said no farting means empty cage, but that doesn’t explain why it seems to go away for most people? Is something being killed off in that time?
A. That’s the million dollar question. I think that lots of farting at first that quiets down after a few weeks is the pattern you want to see. Zero farts from the very beginning usually is seen by people on a VLC diet and probably indicates they are not using the potato starch at all. Mega farts all the time, for a long time, is the one I don’t understand. It seems to be a problem mostly for people who are eating a ton of salad veggies, maybe these people have a robust gut flora from that vegetation fermenters and it just has a field day with the added RS.
Someone once said they cleared up their farts by taking a spoonful of lemon juice at the same time as the potato starch, others have said it cleared up after adding probiotics. Seems it will be different for everyone.  
Q. Are “soil-based organisms” dangerous?  
A. No.
Q. Are SBOs safe for everybody?
A. Only severely immunocompromised people should avoid SBOs.  They know who they are!
Q. S. Boulardii is a yeast...is it dangerous?
A.  No.
Q. I’ve notice some probiotic pills contain polyvinyl alcohol and polyvinylpyrrolidone.  Are these dangerous?
A. Not in the amounts used in the pills, but if you want to avoid chemicals completely, choose a different brand.


  1. Thanks for this fantastic resource, Tim. It's a huge help for those of us trying to tackle the gut as a way of dealing with illness.

    I have a question relating to your recommendations for probiotics (and the use of probiotics in general). I've been reading Prof. John Hunter's book, "Irritable Bowel Solutions". On p. 148 he says that there's a window of "immune tolerance" for a few weeks following birth, during which the immune system doesn't react to bacteria in the large intestine. The bacteria encountered during that period are recognised by the immune system as "self" and survive. Any bacteria encountered thereafter are "vigorously rejected" and can't colonise the gut (called "colonisation resistance"). No matter how many probiotics one takes in adult life, these non-self bacteria won't be accepted.

    He describes this as a theory with indirect support from a study giving L. casei to women in late pregnancy and their newborns. Once the women stopped taking L. casei, it disappeared from their stool but two years later was still present in the children.

    He wrote this in 2007 and I don't know if it's controversial.

    However, if it's true, does it suggest that if someone takes a probiotic containing (for them) a non-self bacterium, their immune system will be under the constant strain of fighting it off?

    Or is it simply the case that this means that for some people, they'll have to be on certain probiotics for life, because they'll never colonise? And that we need to have a stool sample taken before starting probiotics to see what's missing?

    Do we even know what should be in a healthy gut?

    Sorry, that's a lot of questions in the end!

  2. Hi, Sasha - Wow, somebody is reading this! I wondered.

    That theory sounds a bit 'iffy' to me. I've studied this stuff more than I care to admit, and I've never come across anything that says what Mr. Hunter says.

    For instance, how would antibiotics fit into that scenario? Lots of studies show before, during, and after gut biomes when antibiotics are taken. They destroy your normal gut flora and it can take a long time for it to return, but when it returns, it usually doesn't resemble your pre-antibiotics gut.

    However, the probiotics that we take, are generally not meant to colonize the gut. They just help out as they pass through. If there is a niche for them, they might take up residence, but generally they don't. This is not to say they are useless, far from it. These probiotics spread natural chemicals that lower the pH of the gut and can crowd out pathogens.

    I think one of the most important times to take probiotics is before, during, and after taking antibiotics, just to help restore the balance, not so much to repopulate.

    I think most people don't need probiotics, especially if they have good digestion and no real health problems to speak of, and eat a good diet. If someone has really bad guts, and they are trying to heal, then probiotics come into play.

    Nobody should have to be on a certain probiotic for life. Stool tests are useful just to see what you are dealing with, I recommend them highly.

    Do we know what should be in a healthy gut?

    Well, we know what SHOULDN'T be there. Pathogenic strains like Morganella and Shigella, for instance, or major populations of E.coli.

    There should be several large populations of butyrate producing bacteria families like Roseburia, Akkermansia, F. prausnitzi and other Clostridia. But, no there is not a single 'good gut' profile. I suspect that genetics play a big role and also the food you eat and your surroundings, childhood, birth, etc..

    Here is some good peer-reviewed reading, if you like:

    Gut immunity: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3714176/

    Changes in Gut Flora with Diet: http://www.nature.com/ismej/journal/v5/n2/full/ismej2010118a.html

    Thanks for reading! Feel free to ask anything, it's the FAQ section, after all.

  3. Thanks for your response, Tim - I seemed to be frequently asking questions there, rather than posing a frequently asked question (if you see what I mean)!

    That's useful to know that Prof. Hunter's view doesn't seem to be mainstream.

    When people's gut flora are destroyed after abx, is it just that they lack some of the pre-abx bacteria in the long term? I wonder if that could be a lack of exposure. However, if new species of bacteria turn up and colonise, that would go against Prof. Hunter's theory.

    I didn't realise (after all yours and Richard's stuff that I've read, argh!) that the point of probiotics wasn't to recolonise (re-colon-ise!) the gut. I'd read Mr Heisenbug's post about L. plantarum being a "tourist" who benefits the gut's "economy" as it passes through but hadn't realise that that was the norm with probiotics rather than the exception. Thanks for enlightening me! So the point is to crowd out the bad guys to let your existing but weakened colony of good guys get the upper hand and get their numbers up.

    I'll take a look at that paper, thanks!

    I bet loads of people are reading these pages, but lurking. :)

    1. Did you see Jeff Leaches' recent experiment? He put a turkey baster full of Hadza poop up his butt, and plans of doing microbe tests for a year. He has plenty of before tests to compare with.

      This will either confirm or deny Prof. Hunter's theory in a big way!

    2. No, I didn't - urgh, turkey baster - what an image! Trying to get that out of my head now.

      Good for him, though - that's a very interesting experiment. Will look forward to his first report.

  4. I have a question regarding your recommendations for probiotics. I have been taking various brands of probiotics for a couple of years, but only recently started on the RS. Are we supposed to take all four of your suggestions or just any one of them?

    Many thanks for all the information you provide, as well as the copious references. I greatly appreciate it!

  5. My thought with probiotics is that it is a very individual thing. The main goal in all of this is to get good digestion, and in turn, a healthy immune system.

    I don't think there is any need to mega-dose with more than one brand or type. I don't regularly take any probiotics, but I have several bottles and will pop one every now and then, and if I ever had to take antibiotics, you can get I'd be taking one of each every day!

    So, really, you should just assess your gut health and see if the probiotics help. No sense taking them if you still have poor digestion, and not much sense taking them daily 'just because' if you have great digestion.

    I think a good plan for everyone is to eat lots of good fermented foods and forgo the probiotics, but if you are trying to heal after years of poor gut health or immune system problems, then a good probiotic regime and fermented foods could help.

    Hope that helps. Feel free to ask follow-up questions if you have more specific concerns and I'll see if I have any studies or papers on the subject.

  6. Tim - I was fascinated to read your comment on FTA that some probiotics can survive extreme heat.


    I'm guessing that applies to any cooked source of L. plantarum not just beans. I make my own sourdough bread and am delighted that I probably don't kill off all of my very carefully cultivated probriotics when I bake it.

    Can other probiotics other than L. plantarum (which I assume is a lactic acid bacteria) survive cooking?

    1. I think the next phase of probiotics research is going to be in these alternate forms of bacteria and their benefits to us.

      It may end up being that heat-killed probiotics are much better suited to boosting our immune system than live ones. it does seem that many different species are capable of this cell-wall deficient (L-Form) phase and even some yeast species.

      Fermented breads really intrigue me. My Czech grandparents used to make a potato-based fermented wheat bread that rose without any added yeast, they called it 'salt-rising bread'. It stunk up the whole house when going through its fermentation phase, but the resulting bread was unbelievable!

  7. That's very good news that many different species are capable of the L-Form phase.

    Wow! That bread sounds amazing! I have read about various traditional wild yeast breads that are fermented from scratch every time (rather than raised with a continually maintained starter as sourdough is).

    Maybe your next experiments should be with fermented breads, Tim. It's a very addictive and satisfying hobby. I think I remember reading that you don't eat wheat but there are lots of recipes for gluten-free sourdoughs out there.

    A good place to start for anyone interested in sourdough baking is thefreshloaf.com.

  8. Hi again Tim!

    I've been thinking about doses of potato starch and the recommendation that there's no point having more than 4 tbsp a day, which I now suspect existed only in my imagination because on your RS page you say:

    "Langworthy et al. described bloating and discomfort with 180g of raw potato starch and none with 60g. It was also noted that when human subjects were fed over 40g of potato starch, a portion was found in feces, indicating that microbiome may only be able to process up to 40g of potato starch in a single feeding."

    I've been taking 4 tbsp of PS every morning for some weeks. For those of us with immune disorders, I've been wondering if it would be a good idea to maybe take 4 tbsp in the morning and 4 tbsp at night to get a second helping of SCFAs, or maybe even more often.

    Is there any experimental data to suggest an optimal dosing schedule?

    1. I think that 4TBS is overkill, actually. What I like to recommend is eating RS and other fibers from real foods as much as possible, ie. cooked/cooled/reheated beans, potatoes, rice, sweet potatoes, squash, carrots, buckwheat, etc... several servings a day, plus some fruit and lots of veggies.

      On days you don't eat many of these foods, then go for a potato starch nightcap.

      I haven't been able to find anything that suggests a timing strategy or optimal amount, although total daily fiber intake should amount to 20-40g. It's pretty easy to get 20g of fiber from real foods.

      If you are purposely eating 'low carb' it may be harder to get this amount from your food, but nuts and green bananas always help to get the fiber intake up there.

      It's really not worth counting fiber, just eat most of your starches as 'leftovers', cooked/cooled/reheated, and get as many servings of veggies as you can. Snacks like nuts, tiger nuts, cocoa nibs, or dark chocolate also contain good fiber.

      The only theme I see in the RS studies, is the one that says RS is always fermented better when accompanied by other fibers. A low carb diet consisting mainly of meat and low starch veggies supplemented with potato starch is not optimal, in my opinion, although probably better than just straight LC without any fiber.

      I guess, in the end, it all comes down to your individual gut problems and how you are doing health-wise.

      I've seen the 20-40g figure enough to make me think the optimum range is in this area. Would 80-100g be harmful, I doubt it, but it would be very, very hard to hit that target unless you ate raw potatoes all day long. 20-40g is a realistic target and fits within the 1500-3000 cal/day range most people eat in.

      I'd think, if you really like the potato starch as a fiber supplement, 1-2TBS with lunch and 1-2TBS at dinner time would be plenty. RS stays in your system a long time as it gets slowly fermented. Eating it alongside other fibers gets it really mixed in and it travels further along the colon, eliciting more microbial action than if eaten alone.

      Potato starch (or any RS supplements) in a nice smoothy with berries, green banana, etc... is a very good way to get your fiber intake boosted up.

      I know for me personally, it's hard to consistently get 20-40g of fiber, so lots of days I'll end dinner with 2-3TBS of potato starch mixed in yogurt or just cold water.

      There are lots of days I'll just have a green salad for lunch and some fresh, hot rice with dinner...those days I'm lucky to be getting 5g of fiber, And that's how most paleo people eat! I know I ate that way for years, except without any starches or RS sources.

      Pre-cooking starches is an easy way to ensure a good bit of RS. Targeting snacks with RS is another. Smoothies or just RS in water a third.

  9. Thanks, Tim. The PS is hugely attractive to me because I'm quite severely disabled and really struggle to prepare food. I've been on Chris Kresser's 3-month 'reset' Paleo diet, which excludes grains, pulses (and for people like me whose problems might be autoimmune, chocolate) and my health is too variable day-to-day to be able to test those foods and know whether to reintroduce them. Preparing veg is particularly hard work. A magic substance that I can just spoon out and sprinkle on is massively attractive!

    I've been looking a bit shambolically at the other forms of fiber supplements but am a bit confused because some (e.g. LAG) don't seem like things that humans would have been naturally eating. I'm seeing some improvement in my health on the PS and am a bit scared of messing it up by adding in different fibres.

    I've gone a bit stream-of-consciousness there and I'm not sure what my point is, other than that the Paleo, high-wide-fibre diet is pretty hard work to do in some circumstances. :)

    1. I think what you are saying is perfectly acceptable. You are trying to eat healthy, but having a hard time getting enough fiber. Welcome to 2014!

      If you ask your doc, or the kid at Wal-Mart, you'll end up with Metamucil (psyllium) or Citrucel or some other franken-fiber that has very little fermentable fiber in it.

      If you don't tolerate potato starch, and there are those who don't, there is also inulin, FOS, Larch, pectin, and some others. Most are expensive and as you said, not very realistic. I like potato starch because the amounts we are talking are found in one medium sized potato.

      Take care, nice talking with you!

  10. Tim,
    I know you said you don't take probiotics hardly at all but if I were to take one, what do you think of Dr. Tom O'Bryan's Tri Flora?

    Also, prior to doing RS, I was able to get some raw cow colostrum and subsequently had the WORST flair of my autoimmune condition. Now that I am doing the RS, I am considering taking colostrum supplements but am a little afraid of a flair now that I am starting to feel a slight improvement in my condition. What are your thoughts on colorstrum supplementation?

    Thanks for all you do!

  11. I Googled all over for Tom O'Bryan's Tri Flora and could find nothing that said what it is, do you have an ingredient list?

    I don't know anything about raw colostrum, sorry. It seems like it should be a great supplement.

  12. "Multi-Strain Probiotic with Saccharomyces boulardii
    Gluten Sensitivity Tri-Flora™ is a breakthrough combination probiotic formula providing a concentrated synergistic spectrum of Saccharomyces boulardii (SB), Lactobacillus and Bifidobacterium. NuMedica® has chosen the world-renowned Institut Rosell in bringing you the select strains in this formula. Gluten Sensitivity Tri-Flora™ offers protection from pathogens with SB and at the same time protects the intestinal tract through the restoration of beneficial intestinal flora. The three bacteria strains in this formula are proven to be resistant to gastric acidity and bile salts.
    Additional DescriptionMore Details
    Gluten Sensitivity Tri-Flora™ is a breakthrough combination probiotic formula providing a concentrated synergistic spectrum of Saccharomyces boulardii (SB), Lactobacillus and Bifidobacterium. NuMedica® has chosen the world-renowned Institut Rosell in bringing you the select strains in this formula. Gluten Sensitivity Tri-Flora™ offers protection from pathogens with SB and at the same time protects the intestinal tract through the restoration of beneficial intestinal flora. The three bacteria strains in this formula are proven to be resistant to gastric acidity and bile salts. One capsule contains:
    •Probiotic Blend Containing 5 Billion Live Organisms:
    •Saccharomyces boulardii lyo: 125 mg
    •Lactobacillus acidophilus Rosel-52
    •(reclassified L. helveticus)
    •Lactobacillus rhamnosus Rosell-11
    •Bifidobacterium longum Rosell-175
    Other Ingredients: Potato starch, HPMC (capsule), magnesium stearate, ascorbic acid. Gluten Free
    Price: $45.95"

    That is from his website TheDr.com

    Thanks for your answers! I appreciate your honesty.

    1. That looks great! The B. longum is one of the really good bifido's to get. Everything looks good, really.

    2. Thanks Tim! I really appreciate the fact that you share your wisdom with the rest of us - I for one need all the help I can get! Thanks again!

  13. Here's an interesting BBC article about resistant starch (based on a BBC documentary):


    "Just as expected, eating cold pasta led to a smaller spike in blood glucose and insulin than eating freshly boiled pasta had.

    But then we found something that we really didn't expect - cooking, cooling and then reheating the pasta had an even more dramatic effect. Or, to be precise, an even smaller effect on blood glucose

    In fact, it reduced the rise in blood glucose by 50%.

    This certainly suggests that reheating the pasta made it into an even more "resistant starch". It's an extraordinary result and one never measured before."

    Have you ever heard that cooking, cooling then reheating can increase the RS even more than just cooking and cooling, Tim? I'd love to know the details of how long and to what temperature the pasta was cooled, and how it was reheated. I'll watch the documentary to see if it gives more detail.

    As a pasta lover, it's heartening to know that cooking and cooling improves its effects on the body. It's even more surprising given that according to the chart you published on Free The Animal, c&c pasta has a tiny amount of resistant starch. It seems even small improvements in resistant starch are enough to change the physiological effects a food has on the body. It might be worth eating all meals as leftovers in that case, and not just legumes, potatoes and rice.

    It's good to see the resistant starch story going mainstream. It must give you a nice, warm glow Tim. :-)

    1. Here's a second article which goes into more detail about the results:-


      It seems the pasta was chilled in the fridge.

    2. I've watched the documentary now. The pasta looked like white pasta and it was chilled in the fridge overnight. We weren't told how the pasta was reheated.

      It was only an N=10 experiment, but all the volunteers had similar results.

      If nothing else, this documentary has made me think about eating all my starches as leftovers, not just ones with higher levels of RS.

    3. Heather, I am soooo with you on that!

      Eating hot, fresh food 100% of the time is a modern invention. People turn their nose up at leftovers, but we should in fact, be preparing our food as 'leftovers' for maximum benefit.

      The poor, rural Africans that have no colorectal cancer subsist mainly on 'stale maize porridge.' They make a big pot and eat it cold or reheated for days. There's a lesson there!

      Thanks for the link to the pasta article, I think it will make its rounds quickly.

    4. About this article about pasta, cooking and cooling, here's what Dr. Davis (wheat belly) says about the article,

      "Please do not fall for this bit of imprecise thinking. The process of “retrogradation” of sugars back to fibers is relatively minor, e.g, 10%. It means that 90% of sugars remain in sugar form. Cooling is therefore NOT a safe way to obtain resistant starches."

      what do you think, Tim?

    5. I should think his advice should be: "I don't care how much RS, don't eat f*cking wheat!"

      I think, otherwise, he is mistaken if he is saying that the RS found in cooked and cooled rice, beans, and potatoes is 'inconsequential.'

      Consider this: If you are on a grain-free, paleo diet, as WheatBelly prescribes, and you are eating potatoes, rice or other 'safe starches' like Perfect health Diet prescribes, you are only getting 0-2g/day of RS...less than the SAD diet!

      Pre-cook, cool, and serve your safe starches as 'leftovers' and your RS intake will jump to 10-20g/day.

      A "relatively minor" 10% increase in RS in massive to your gut!

      I'm not sure where Dr. Davis stands on carb intake, but I thought he was in the 100-150g/day camp. If this is coming from starches, why not precook and serve as leftovers? Easy tweak!

    6. re: A "relatively minor" 10% increase in RS in massive to your gut!

      The concern is that the other 90% bumps BG.

      re: I'm not sure where Dr. Davis stands on carb intake, but I thought he was in the 100-150g/day camp.

      Under 50 grams net carb per day, 15 per meal or 6-hour period. Fiber carbs is unlimited, so there is no specific limit on total carbs (and I can't recall even seeing a ballpark figure). On RS, his current rec. is 20 grams/day (subject to change, as new actual results and unconfounded science rolls in).

    7. Welcome Boundless! So funny. I was JUST reading some comments you made about zonulin/leaky gut on Wheat Belly in 2012 (http://www.wheatbellyblog.com/2012/11/what-do-you-have-that-chimps-dont-have/) and wondering what you've been up to.

      Thanks for the input. I have given lots of thought and hear lots of questions about how to best reconcile gut health/prebiotics/low carb eating.

  14. Tim,

    I think I read somewhere on this site that potato chips are not a good source of RS3. I was wondering why? It seems like they should be because they are cooked and cooled. I understand avoiding most because of the oils they are cooked in but I just found these at my local whole food market http://www.honestchips.com/order-online.

    1. I'm somewhat against all deep-fried foods, no matter the oil. There is a substance known as acrylamide that is thought to be a carcinogen and is especially high in fried foods.

      As an occasional snack, sure. These look great.

      Actually, potato chips are a great source of RS, in fact, probably the #1 source for most SAD eaters. But as a food choice, potato chips is not high on my list.

      I have been known to eat a handful of Bugles and I'd try a handful of these Honest Chips, but I don't think I would want a bag in the house as I'd be tempted to eat the whole thing.

    2. I did a search on acrylamide and found this -
      This indicates that acrylamide is formed during baking and roasting also. It's in coffee, too!!! Just shoot me now! BTW I suggest you stay away from those chips as they are absolutely delicious!

  15. http://www.prevention.com/food/healthy-eating-tips/

    This article says NOT to heat the resistant starch foods after they have been cooked and cooled... I know there is a lot of wrong information out there and I trust you more than most of the others out there jumping on the bandwagon... So I wanted to verify that reheating the resistant starch foods does not damage the resistant starch. (I think Chris Kressler says not to reheat them above 130 degrees.) Also, do potatoes have to be cooked just one certain way prior to cooling? I have to wonder if there aren't some out there who try to make this more difficult than it has to be....

    1. Disregard this - I found all the info I needed on your site. Thanks!

  16. Hi Tim
    Leafy green salads, potato starch and gas.
    I had read a post of yours somewhere where you had said people have had more gas issues with this combo. I'm one. I eat salad every day, various lettuce types, veggies, and always with raw red onion. Been supplementing 4 TBS BRM daily, 2 in the AM with filtered water (empty stomach), and 2 in the evening. 1 TSP inulin in the AM, and glucomannan every 3 days or so. Prescript assist and a vitacost brand of probiotics about every 3 days. Been doing this since July and the gas has been epic. Usually in the morning it is not much of an issue until I eat something, around 1:00. Katy bar the door at that point. Been paleo for 2 1/2 years, gave up on ketosis after reading plenty of articles by you and your compadres (great work by the way). Went from 203 to 143, now back up to 155 after starting PS and eating more carbs.
    Anyway, thoughts on the gas?

    1. Maybe stop the potato starch for a week or so and see how you do. Then add back in 1-2TBS a day if the gas dies down. I would guess your gas is from the inulin and onions. Maybe try cutting those out for a few days and see. You seem like you are getting plenty of fiber in your diet. Plenty of room to play.

      I think if a person is eating a fiber filled varied diet, probably 2TBS total supplement is way plenty to ensure you are getting enough fiber.

      If your digestion and health is otherwise great, you are pooping without any issues, and you can eat all kinds of food without problems, your gut health is fine. Just play with the excess fiber until you find a combo that is less 'noxious.'

  17. Tim, about acrylamide. So what would be the distinguishing factor of frying food that creates this above what would happen when you bar-b-que a fatty cut of meat? Would not the fat on the exterior of the meat get to the same frying temperatures? Or are you talking about only 'deep fried' foods, which usually means heating the oil at high temps for extended periods of time - over and over as in the case of fast food makers of french fries.

    1. Good article here: Hold the Fries!

      I really haven't paid too much attention to the acrylamide issue. I don;t eat any deep fried foods any more and try not to scorch meat.

  18. Which prebiotic fibers (RS) remain largely or entirely RS after cooking (and serving immediately, warm or hot)?

    Potato doesn't, although some is recovered on recool. I'm guessing that inulin might survive, but I don't even have guesses for the long list of other sources.

    1. The big RS sources (RS2, raw starch) all disappear when cooked. Some do turn to RS3, but at only a fraction of the original content.

      The other prebiotic fiber, inulin etc... do seem to be able to withstand cooking/heating, but they are in such low amounts in the foods we eat that it's hardly worth counting/worrying.

      I think you need to go out of your way to get meaningful fibers. Raw sunchoke, raw onion, green banana, raw potato, raw garlic, seeds, nuts, etc...

      But the cooked veggies have stuff in them, too, and some nutrients may be unlocked by cooking, so best is probably a mixture of cooked and raw.

      Hey, we are having a little leaky gut convo here, come join in!


    2. re: The other prebiotic fiber, inulin etc... do seem to be able to withstand cooking/heating, but they are in such low amounts ...

      Not when used as a recipe ingredient, and inulin is widely available for the purpose. It is thus important to know if it can be used in recipes that require cooking. Sounds like the answer is yes.

    3. What about just eating beans after they have been soaked/fermented, boiled for at least 15 mins, and then slow cooked for ten hours or so? There is a lot of fermentable substances leftover from all the cooking, it is extremely cheap, and the net carbs are pretty low. About 20 grams for half a cup after you take out the fiber and indigestible sugars. Beans supposedly result in a large amount of SCFA, and reduce digestive track cancers.

    4. I'm a huge fan of beans. I'm on the fence about soaking (fermenting). It definitely changes the structure of the bean, fiber-wise. It makes sense to ferment, but I can also see some reasons not to soak. I try to eat beans a couple times a week. I usually make a big batch, pre-soaked 24 hours, then freeze in individual portions until ready to re-heat and eat.

      Sometimes I'll make bean soup with dry beans, and sometimes I'll eat canned beans. I never waste beans served in a Mexican restaurant, either!

      I think over time, eating them in a variety of ways ensures you get the best of what beans have to offer.

  19. Could you expand on the reasons not to soak beans and legumes?

    1. Well, when you soak beans, you are recruiting bacteria to start to degrade some of the fibers in the bean. There is something called raffinose in beans that leads to much of the gas produced when eating beans, but soaking can eliminate about 90% of the raffinose. Also, much of the insoluble fiber is converted to soluble, and some nutrients are made more available when soaked.

      Soaking seems to make the beans more beneficial to YOU, but less beneficial to your gut bugs. See where I'm going?

      I would never say, 'you must not soak beans' and I would also never say, 'you must always soak beans.'

      Soaking them is easy enough, so if you have time, why not?

      Here is some good reading on what happens when you soak beans:


    2. My understanding was about 50% of the raffinose will dissolve into the water during soaking... I just cook with the soaking water instead of discarding it. I am attempting to reduce the lectins by fermenting. Also, I seem to still be getting plenty of "food" for my gut bugs without going into too much detail. Do you think lectins are a concern, or the reduction in "gut bug food" is not worth the trade off?

    3. In light of operating with a healthy gut, I don't worry much at all about 'anti-nutrients' at all. Much of what 'paleo' deemed poison actually maybe be beneficial in a controlled way.

      Still, with beans, I think a bet-hedging strategy is best. Soaked, unsoaked, canned even. Rotate them through your menus.

      That 'trade-off' you mention...who can really say? As 99% of America is living on less than 15g of fiber daily and only 3-5 of it fermentable, we see where that gets us. Beans, no matter soaked or not, are a great source of fiber. Use them however you like. I think the tradeoff is not worth worry about.

      But just for sake of discussion, I can see benefits to both sides. Soaked, they will be filled with lactic acid producing bacteria that are just as beneficial when heat-killed. Unsoaked and you get more food for your own gut bugs.

      Probably is no right answer.

    4. Thanks. I think i saw someone mention this earlier, but how are the heart killed bacterial is beneficial?

    5. Quite a bit of research has been done on heat-killed probiotics. they have been used in veterinarian probiotics for years, and just now appearing in human probiotics.

      Here's a nice paper on the subject, humans, from 2006.

      Daily Intake of Heat-Killed Lactobacillus plantarum L-137 Augments Acquired Immunity in Healthy Adults


      "Heat-killed Lactobacillus plantarum strain L-137 (HK-LP) is a potent inducer of IL-12 in vitro as well as in vivo in mice. HK-LP has been shown to suppress IgE production against food allergens, as well as tumor growth in mice, through IL-12 production, which induces the T helper (Th) 1 type immune response. To determine whether the intake of HK-LP influences immune function and the quality of life (QOL), a randomized, double-blind, placebo-controlled, parallel study was conducted in healthy subjects. Sixty subjects (30 men and 30 women, mean age 56.3 y) were randomly assigned to receive a capsule containing 10 mg of HK-LP daily or a matching capsule for 12 wk. Biomarkers for innate immunity such as the natural killer activity of peripheral blood mononuclear cells, neutrophil phagocytosis, and cell surface expression of CD64 on monocytes were measured every 4 wk. Biomarkers for acquired immunity such as concanavalin A (Con A)-induced proliferation, percentages of INF-γ and IL-4–producing cluster of differentiation (CD)4+ T cells (Th1:Th2 ratio), and the serum IgG4:IgG ratio were measured every 4 wk or at wk 0 and wk 12. Health-related QOL was assessed using a self-rating questionnaire with 26 items. Among the measured biomarkers, the percent change in Con A-induced proliferation and the Th1:Th2 ratio in the HK-LP group was greater than those in the control group (P = 0.036 and P = 0.002, respectively). The degree of improvement in QOL was higher in the HK-LP group than in the control group at wk 8 (P = 0.049) and tended to be higher at wk 12 (P = 0.092). These results suggest that a daily intake of HK-LP augments acquired immunity, especially Th1-related immune functions in healthy subjects, thereby improving the health-related QOL."

      I could probably get the full text if anyone was interested in seeing more, but I think the tl/dr version is that these dead bacteria two two things:

      1. transform into a more resilient form of themselves (not actually dead)
      2. act as a template for the immune system without potentially causing harm

    6. That is interesting. Thank you!

  20. I can deal with the consequences of not soaking the reason to eat them is for the gut bugs. Thanks :) Practically, this blogpost was interesting.


    1. Read the link, Allison. Thanks for posting.

  21. "When you get these probiotics, take them every day, just once a day no matter what it says on the package"... A quote from the faq on probiotics above, Tim.

    May I ask why just once per day?

    1. Just my opinion. I have not seen any evidence that you need to take boat-loads of probiotics, but the manufacturers would really, really like you to empty the bottle as fast as possible.

      And maybe even once a day is too frequent. But, it all has to come down to your personal preferences and starting point. Maybe taking a probiotic with each meal is better for you, but, we really don;t want a gut that is reliant on probiotics, we want our own communities. If probiotics were all they are cracked up to be, you'd only need one pill and it would create a thriving community.

      I think that most probiotics do there "magic" as transients. But, once a nice microbiome is established, just frequent sightings of these friendly strangers should be enough to mimic the natural eating patterns of novel microbe ingestion.

      After all, that's what we're trying to do, right? Recreate a more natural eating pattern by ingesting new species of microbes from time to time.

      Not sure if it says it in the FAQs, but even better, if you like probiotics, would be to buy 4-5 different types/brands, and just mix and match throughout the weeks. Skipping some days, doubling up on others. Just show your gut microbes that you are inviting these other people to dinner and if they want to "make friends" they can.

      In the gut, it's all about filling niches, no? The goal is to have a gut dominated by non-pathogens. Any empty spot will be filled by something. To ensure the bad guys never get a foothold, it's important to eat food that friendly bacteria like, which will in turn create a pH suitable for friendlies, and unsuitable for pathogens. The bacteria that take over your gut are more a byproduct of what you eat, and not the microbes you try to ingest through probiotics. Babies guts are a prime example.

      Thanks for the question!

  22. I've been wondering if Cassava (tapioca) starch would be a good addition to my prebiotics. In researching this it is difficult to get a handle on the resistant starch content of Cassava. Part of the problem may be mis-labeling flour as starch and the other part is the multiple names this product is known as around the world, the amount of processing it has undergone, etc.

    Can you throw any light on whether Cassava starch is a suitable prebiotic?

  23. I am loving this site. Great info and good humor. Thank you! Soooo...when I eat beans, I do not fart. Beans have never made me fart. When my husband and daughter eat beans, they fart like crazy. We're eating the same beans. What clue might this be to the demographics of our colonic population?

  24. Hi Tim,
    I just wondered if you were still interested in RS effects on SIBO. Recently in Chris Kresser's interview with Dr. Pimentel, this study was brought up: http://www.ncbi.nlm.nih.gov/pubmed/20937045 and now Dr. Pimentel is treating some patients with Rifaximin and PHGG. He uses the prebiotic to bring the bugs out to be happy and fed, where the antibiotic can get to them. Then, when Rifaximin is stopped, so is the prebiotic and back to a low Fodmap diet. What do you think of that? Also, while we're on the topic, did you see this study? http://www.ncbi.nlm.nih.gov/pubmed/26239401 Sibo is considered a form of IBS. I have SIBO and have taken 3 TBS BRM PS since fall 2013. I retested last month and my numbers are very similar, so it probably hasn't made the condition worse and certainly it has helped tremendously with chronic C. If I don't take it everyday, it starts to return. I am about to start Xifaxan for the Sibo, finally, but I will continue PS at least until the end of treatment. Thanks for all you do!

    1. I did listen. Interesting. Glad people are trying different things. It makes sense what he says, when you starve the microbes, they burrow in deep and hide.

      Once dysbiosis sets in, ie. SIBO/IBS, it is tough to get over it. I know lots of people who say the same thing: RPS works great, but have to take it every day. Maybe not such a bad thing. Better than meds.

      Good luck with the SIBO.

  25. Just found your website and not sure where to post this - sorry! Have dealt with chronic constipation for 40+ years - have tried what I thought was everything on the market - but having found your side and the Homeschooling Doctor site brought butyrate to my attention for the first time! Question: starting from scratch, ordering potato starch and a probiotic (though I've taken one for years - maybe time to mix it up?) - I've read thru so much of your site that my head hurts, though I loved the last two days spent here! BUT what do I do, where do I start? Should I be using Betaine hcl with Pepsin or digestive enzymes at the same time? An actual butrayte supplement? ANY help, suggestions, comments will be so appreciated by this 68-year old dairy farmer's wife in Ohio!!

    1. It all depends on one thing: Where in Ohio are you from?

  26. Tim, in regard to the dried plantains, my health food store sells these in snack size bags. Do they have to be green and then dried to get the RS benefits? These do not say green plantains so I am wondering if they are worth the calories... Thanks for your help!


    1. Yeah, tough call. There is also probably some kind of oil involved I would guess. Probably OK for a treat, but not a daily source of RS.

  27. Gina,
    They are green plantains. If they were not, I would think it would be much harder to dry them and they would taste very sweet. What you need to be careful with is what oil they use and the preservatives. Not sure about the RS benefits.

    1. Thanks Tim and Navillus,

      The package says they use palm oil, plantains, and sea salt. Yes, they are a great treat when I want something crunchy and salty but it looks like popcorn is a great option too!


  28. Hi Tim,

    Thanks for putting up such great information about RS and probiotics.

    2 Quick questions:

    Do you know of a way to maximize the quantity of RS that reaches the far ends of the large intestine? For example to minimize the possibility of feeding bacteria near the large/small intestine juncture (which is especially important for people with SIBO) and to make sure that bacteria are fed not only at the start of the large intestine but all along?

    RS3 seems to provide more benefits that RS2. If RS3 is created by cooking/heating and cooling RS2, would it be a good idea to heat Bob’s Red Mill PS (in a pan or oven for example) in order to make RS3 from the initial RS2 only product?

    Thanks in advance for the information.


    1. Marc - As far as I am concerned, there is no difference in the RS sources you include as part of a healthy diet, ie. a diet containing meat, fat, and plants.

      If you were to eat an isolated RS source, potato starch for instance, and see what happens to it, it would most likely be fermented mostly in the first part of the large intestine (cecum), whereas other isolated starches/fibers might travel a bit further.

      When included in a diet rich in plant matter and other fiber types, I believe that all parts of the large intestine will benefit. The reason I say this is because in studies where they look for such things, raw starch is commonly found in the feces. This means the entire colon had access to the raw starch, ie. potato starch (RS2).

      Raw PS contains about 75% RS. If you heated it and let it cool to form RS3, it would contain maybe 2-5% RS. There is just not a big return on turning RS2 into RS3.

      If I may offer a suggestion, simply precook all of the potatoes, beans, and rice that you eat and store in the fridge or freezer. If you want to add a supplemental starch, use cheap potato starch and don't worry about where it ferments. After a while, your gut bacteria will expand to meet the supply if fiber.

      So, I guess to answer your original question: To maximize the quantity of RS that reaches the far end of the large intestine, simply start eating a diet that is rich in fiber (30-50g/day) and supplement with something like raw potato starch, banana flour, or inulin if you are not hitting that target regularly.

      To answer the SIBO part...sorry, no idea. Try different things, each person's SIBO seems unique to them.

  29. Hi Tim! Thank you very much for such quick response and for the useful tips! So in summary, you recommend to mix different fibre types (like mixing natural sources of fiber with inulin and RS for example) to maximize the amount of RS that arrives to all the large intestine?

    Regarding the amount of RS, does the potato temperature at time of consumption make a difference in the amount of RS consumed or the only thing that matters is the amount of heat/cold cycles it has received? In other words, does it make a difference to consume the already cooked potato cold or reheated?

    In the question about RS in cold potatoes, it says:

    “Raw - contains about 30g of RS
    Cooked - 1g
    Cooked and cooled - 3g
    Cooked, cooled, reheated - 5g
    Cooked, cooled, reheated, re-cooled - 6g”

    From that info, I’m assuming that reheating is good and the more cycles the better. Until now I thought that reheating a cooked potato would re-destroy its RS and it had to be consumed cold to benefit from the RS.

    Also, do you recommend a particular way to consume a raw potato (to maybe avoid parasites, pathogenic bacteria, etc.)? Or people are safe to just peel the potato and eat it cold?

    Thanks gain!


    1. I think a high natural fiber diet is best, especially when you pre-cook and cool most of the starches you eat. But also lots of mushrooms, nuts, onions, garlic, and just plain old fruit and veggies of all kinds. Then, if you feel you want to supplement, use a couple spoonfuls of inulin, potato starch, Hi-Maize, or banana flour for instance. It really is that simple.

      Reheating a potato increases RS with each cycle, But never as much as the first cycle, if that makes sense. Diminishing returns. But feel free to heat and cool as often as practical. This is a trick used by the food indistry to make RS3 powders that they then put in processed foods for "more fiber", then heat and cool starches hundreds of times in patented processes to make high RS sources from starches that normally contain very little RS (tapioca, corn).

      re: Raw Potato. Eat how you like. When I am cooking potatoes, I always eat a slice or two raw. It is kind of a self-limiting endeavor, eating raw potatoes, lol. As long as they are clean, it's no different than eating a raw carrot or radish, as far as food safety goes.

    2. This add to what Tim says:

      My goal has never been to maximize RS in the distal colon. I'm not even sure that makes sense as a concept. Maybe the distal colon is meant to digest stuff that is more complicated.

      Like Tim says, I think there is a lot of value in eating natural foods. Alot of recipes/common knowledge dispose of the good parts of plants. I love the greenest parts of leeks. The branches of fennel. The ribs and stems of collards and kale. The woody ends of asparagus. A lot of recipes tell you to toss these. No! Eat them if you can. Plus onion and garlic skins.

      Seeds: I eat lots of stuff with seeds now. Figs, tomatoes, cumin, sesame seeds, seeds in chiles. It doesn't seem to be coming out the other whole, so I guess I'm digesting it?

      One caveat re potatoes: As I understand, with regular potatoes the farmer spreads a herbicide to kill the plants so that it is easier to harvest them all,at the same time. This cannot happen with organic potatoes. While I cannot speak to the veracity of this, I can say that I can keep regular potatoes in my counter for several weeks without sprouting. They are dead. Organic potatoes sprout within a few days. I only eat organic.

  30. and all those farts the fibre produces.......

  31. Hi Tim,

    I have a few questions that probably other readers have also been thinking about:

    - We know that probiotics alone are not very effective if they are not fed properly (with prebiotics) once they are in the gut. In this case we have talked a lot about the benefits of RS. However, does RS feeds predominantly some species of bacteria and not others? For example will it feed mostly Lactobacillus and Bifidobacterium and thus increase their numbers predominantly or will it feed mostly all bacteria equally (even SBOs)?

    - Following my first question, do you know what could be the best way to feed selectively bifidobacteria in the gut (more specifically the Bifidobacterium Infantis species), specially after using antibiotics? I know that RS is an excellent prebiotic for Bifidobacteria but don’t know if it feeds equally well the other micro biome species. Maybe there is a more selective prebiotic or is there a way that RS could be used that could make it more effective at feeding mostly B. Infantis?

    I googled a lot trying to find the best prebiotics for specific kinds of bacterias (Bifidobacteria favorite foods, etc.) but couldn’t find any good info on the subject.

    Thanks in advance,


    1. "...does RS feeds predominantly some species of bacteria and not others?"

      Yes, that seems to be the case. It appears to predominately feed a group of bacteria that have beneficial effects on the gut. RS is not a simple starch that is easily digested by bacteria, it takes several different species to break RS down into the desired end-products of short chain fatty acids, ie. butyrate. This complexity is what seems to make it so beneficial. The byproducts of the different stages of RS fermentation go on to feed other bacteria, such as bifidobacteria, who cannot ferment RS on their own. It also creates an environment with a pH more suitable for friendly bacteria than pathogenic.

      ...do you know what could be the best way to feed selectively bifidobacteria in the gut (more specifically the Bifidobacterium Infantis species), specially after using antibiotics?

      This is a mystery. I've seen otherwise healthy people eating all the things that should promote bifidobacteria whose gut test reports show no bifido. I've also seen gut test reports from people eating a low fiber diet that do have bifido listed on their stool tests.

      Personally, I've had massive blooms of bifido after supplementing with potato starch, and they all but disappeared when eating plain potatoes, only to return a few weeks later after ramping up the natural fiber.

      This all tells me that chasing a mystical bacteria by name is a futile game. The tests to find it are faulty, and there is also evidence to suggest that many different bacteria can be equally as beneficial. I think the best bet for anyone is to eat a diet that settles well in their stomach and leads to great digestion, ie. non-smelly, infrequent gas, well-formed, regular stools, lack of bloating and pain, etc...

      Fermented foods, including cheeses like Brie and blue cheese, as well as sauerkraut and other fermented veggies on a near-daily basis is usually a good idea. Eating a wide selection of fibrous foods such as garlic, onions, leeks, cabbage, asparagus daily is a good idea. Oatmeal for breakfast many days a week is recommended. A supplemental dose of a prebiotic such as inulin or potato starch can be used daily, or on days when you were slacking in the fiber department.

      The elusive B. infantis may or may not take up residence, but equally beneficial microbes will enjoy this feast and come together just like "Pilgrims and Indians" to feast together and form a beneficial union of gut protectors.

      Happy Thanksgiving!

    2. Thank you very much for the great answer! That’s some very useful information.


    3. And Tim, do you think it is possible (at least with the level of knowledge we have now) to make probiotics really colonize the gut to shift the bacterial populations proportions long term?

      From what I’ve read probiotics in general seem to only have a temporary benefit and they don’t seem to be able to repopulate the gut (after antibiotic use for example). Even the probiotic manufacturers themselves suggest (by the label wording) that their product only provide a temporary benefit. It’s almost like if manufacturers only make probiotics that are aren’t able to repopulate the gut in order to make customers to buy again their product to keep getting the benefits.

      However the combination of probiotics + effective prebiotics (like Resistant Starch) seem to be the key (or a first step) towards making probiotics more effective and being able to shift the bacterial ecosystem long term in the human gut.

      Here’s a simple example: let’s say that a child is born by C-section and so his microbiota has less beneficial bacteria than the ones of standard delivery children. Fast forward 20 years, the same person now an adult has whatever bacterial populations that first colonized his gut, deeply established on it. In this case, beneficial bacteria consumed with probiotics technically would have trouble establishing in the gut because they would constantly be overcrowded by the already established bacteria.

      In this case, do you think there could be a way to make lacking good bacteria recolonize the gut? I think a good way would be to use some kind of antibacterial treatment (herbs or standard antibiotics) to diminish all bacterial populations (to minimize the chances of overcrowding), then take some strong probiotics with lots of beneficial bacteria (like VSL#3 and Prescript Assist) and couple that with RS and other fibers (inulin for example) to feed those same probiotics. Do you think this could be a good strategy? Do you have additional insights about it?

      Thanks a lot,


    4. While I have read many convincing research articles that probiotics can help stimulate the immune system and lead to better overall gut health, I don't believe I am convinced that the species themselves will eventually become a part of one's gut flora.

      It's more likely that the introduced probiotics are seen as 'intruders' and the immune system launches an attack and/or other bacteria see them as intruders and in their attempt to kill them, they kill other pathogens as well.

      I think that the gut flora is much more robust than people give it credit, I also think that the bacteria you need will get there on their own. In the event of poor digestion or other symptoms that point to an imbalance in gut flora, probiotics are worth a try. Some people respond exceptionally well, others only after experimenting with different probiotics, and others not at all.

      Your thoughts on recreating a new microbiome have merit. Antibiotics would be a last resort, but herbals and foods like garlic that exhibit antimocrobial actions can be safely used by anyone, anytime as they will only strengthen an otherwise stable gut flora, as well as kill off pathogenic overgrowths.

      One thing I would recommend as well: probiotic yeast like S. boulardii. We all focus on the bacterial populations, but there is also a fungal component to a healthy gut and S. boulardii can help stabilize it.

      But, I must caution, once extreme gut dysbiosis sets in, it is very, very hard to diagnose the exact problem and people spend years and years trying to fix it. From what I have seen and heard, doctors (even naturopaths) usually just mess things up worse, but it may be in your best interest to get a doctor involved to rule out things like Lyme's, H. pylori, C. Diff, etc... or mechanical defects that can cause gut dysbiosis.

    5. Thanks for the great points. I agree that the average doctor (and even some naturopaths) lack the required knowledge to work with the gut bacteria. However functional medicine practitioners seem (in general) to have the required knowledge to really tackle the problem of dysbiosis so right now they seem to be the only ones to whom a patient can go if they really want to treat whatever gut problems they have.

  32. Hi Tim,
    What are your thoughts about diatomaceous earth? I used it for a few days but stooped when I saw that I had blood in my stools. Do you think it kills off good and bad bacteria, if there is such thing ? Should I use it?

    1. I have a pretty hard rule in life: If it makes my butt bleed, stop doing it!

      DE has some antimicrobial properties that make it useful in certain situations, but I have never looked at it very closely as related to overall gut health.

      I've used it in my chicken coop and garden, but never purposely ate any.

      It's a fascinating, natural product. Made of fossilized algea (diatoms). I'd have to do a lot more research before I could give it a 'thumbs up.'

    2. Don't they use diatomaceous earth to kill cockroaches or something like that? http://www.thekitchn.com/how-to-get-rid-of-cockroaches-89079

  33. Hi tim,
    What do you think about gluten? Is it inherently bad ? Or can people with good guys tolerate it? Also I have read about einkorn and it is interesting. Do you think that not having any digestive complaint after eating gluten from Einkorn or other sources is enough to prove that it isn't harming you?
    Thank you very much

    1. I think that gluten sensitivity needs to be evaluated on a case-by-case basis. In a normal, healthy gut, gluten is tolerated just fine. Many hundreds of generations of humans have proven this.

      In our modern day where nearly everyone has gut dysbiosis of some type, going gluten-free is helpful to most people to some degree. Gluten appears to have many evil abilities to interfere with proper gut function, as Dr. Davis explains in Wheat Belly.

      However, with a healthy gut, ie. one fed ample fiber and giving its owner no problems of "nausea, heartburn, indigestion, upset stomach, diarrhea," as the Pepto-Bismol jingle describes, one should be able to eat wheat whenever they like.

      I would like to add a caveat though. I don't think that modern, white, processed, and enriched wheat flours have a place in the human diet. If you want wheat flour, eat whole grain, unenriched types. I think that modern processing of wheat into the all-purpose flours we know today destroys all nutritive value of the wheat and greatly increases the glycemic index to where it is basically worse than white sugar, gluten or not.

  34. Hi Tim, I agree with you about processed, enriched wheat being bad. But do you think all modern hybridized wheat is inherently bad? A lot of people seem to think that the wheat today is not the same as it once was. So maybe ancient wheat like Einkorn would be better for us and our guts?

    1. I'm not so convinced of that. Modern wheat is mostly the result of natural selection in plant breeding, although Dr. Davis makes some convincing arguments, I'm not sure that modern wheat, when eaten with its bran, germ, and natural oils are the evil thing he portrays. However, how much modern wheat is eaten in a traditional, whole-wheat, coarsely ground manner? Not much.

      The ancient wheats, Einkorn and Spelt, would also be just as problematic, I believe, if they were refined and enriched. But eaten as whole-grains, they are certainly a really good food choice.

  35. Hi Tim, When I eat oatmeal should I eat it cold to get the most resistant starch ? Is there a significant difference is the RS content of cooked oats and cooked and cooked oats?
    Thank you

    1. Makes no difference. You can add uncooked oatmeal or oat bran to smoothies or whatever, or you can cook it and eat it hot. The little bit of RS3 you lose by eating it hot is offset by the large amount of beta-glucans present in oatmeal. The Beta-glucans are not destroyed by cooking.

  36. This has nothing to do with potatoes or RS... But I was wondering about your thoughts on near infrared or far infrared therapy....

    1. Sorry, Gina - I have no idea what those even are regarding a therapy. Most likely I will find it quite unnecessary, if I can't get the rays I need from the sun I'm not sure I want to get them from a machine.

  37. Hi Tim,

    I've read on multiple sources that RS could be helpful for SIBO because the excess bacteria would somehow bind to the RS fibers and make them end up in the large intestine, effectively clearing the small intestine of the excess bacteria. I know this is mostly a theory right now because, to my awareness, there hasn't been a study that proves this but this theory makes sense. There is some interesting information in the following article:


    What'd be your input on this? Do you know of anecdotal evidence that suggests that RS could be effective in complementing a SIBO treatment?

    Thanks a lot,


    1. I was interested recently in something related called "contrabiotics". Not fo SIBO precisely, but there have indeed been studies for certain pathogens in the large intestine.

      Here's an overview.


      Do a search on contrabiotics and you should find some interesting ones.

      It turns out that the shape of the starches matter. Plantain and broccoli do well for some, inulin does not. This might be a good argument for getting a broad range of fibers/prebiotics since dysbiosis could be represented by a range of pathogens.