You may have heard that ninety percent of the cells in our bodies do not share our DNA. We are mutually dependent on the billions of microbes that live in us, on us, and around us. We were never meant to live in a sterile world. These friendly aliens must be nurtured, tended, and replenished if we want them to stick around.

Many foods contain a kind of starch that is not digested by human enzymes so it survives until it reaches the colon, where it is broken down by bacteria and turned into short-chain fatty acids that feed the gut lining, improve overall health, and prevent and treat a number of diseases. Beans are notoriously high in resistant starch (RS). It is also in some other foods. including potatoes, rice, tapioca, green bananas, and plantains, but most of them contain a lot more plain ‘ole digestible starch than RS and when they are eaten hot or reheated, it all becomes digestible. Most advocates of RS supplementation prefer to buy flours that are just the extracted RS; the most popular one to use is raw, unmodified potato starch (RUMPS) from Bob’s Red Mill. Note: The downside is that eating the same kind of prebiotic fiber regularly may cut down on the diversity of your inner microbe community so it would be wise to explore some other sources in addition to potato starch, You want to keep your intestinal tenants happily evolving, interbreeding, and inviting their pals to the party.

I don’t pretend to know a lot about RS, so I’m going to hand you off to the experts to do your own research. You can read about the pros and cons via the links at the bottom of this post. Most, but not all, of them think that there are advantages to using it, although Jimmy Moore cautions that RS set off such cravings for him that he had to quit eating it and Dr. Norman Robillard, author of Fast Track Digestion, suggests caution for those with gut or auto-immune issues until their symptoms are under control. He says that for healthy people, it may be beneficial as long as it is not eaten in excess. Here’s a quote: “To be on the safe side, people with Small Intestinal Bacterial Overgrowth (SIBO)-related digestive illnesses such as GERD, IBS and Celiac disease, to name a few, would be best served by consuming lower levels of resistant starch because it behaves much like fermentable fiber.”

As you can see, there may be digestive repercussions to eating indigestible starches. Mark Sisson recommends starting with 1/2 to 1 teaspoon of RS potato starch and working up to 20 to 30 grams from there. Dr. Eefeldt suggests working up to 2 tablespoons a day. There are about 8 grams of RS in a tablespoon of Bob’s Red Mill Unmodified Potato Starch, so 2 and 1/2 tablespoons equals 20 grams. If you use my soup recipe as a base, you can add as much RS as you like (or as much as you can tolerate) to individual servings and ramp the dosage up gradually. Remember to add it just before serving and after the base is cooked and cooled. You may need to stir it occasionally between spoonfuls so the RS doesn’t settle out. If you decide that RS supplementation is not for you, you can still enjoy the soup; if you only heat it once and then eat it warm or cold, some of the regular potato flour will become resistant, which will have the added bonus that the carb count will be even lower than what is shown.


A major problem with eating raw, indigestible starches is that all of them taste horrible. I thought it would be convenient to dehydrate some plantains so I could easily grab a few slices to get my RS quota. The ones in the picture are still sitting in my cupboard because they taste so BAD.Sure, you could just stir your daily dose of RS flour into a glass of water, hold your nose, and gag it down, but it seems a shame to waste a chance to cheat without enjoying it!

Vichyssoise seemed like the obvious place to start when looking for a recipe to hide the taste of raw potato starch. I kicked up the flavor in my low-carb Potato Soup from Carb Wars; Sugar is the New Fat to use as the base. After it is cooked and cooled until just warm, you can stir in however much you want of the raw potato flour. (But keep the temperature below 140 degrees or the starch will become digestible.) If you want to serve it cold, you may need to use a liquid fat like olive oil rather than butter, which might harden in the soup when it chills.

2 cups chicken broth (more if needed to thin soup after adding RS)
2 Turkish bay leaves
1 celery stalk with leaves
1 medium onion, peeled and cut into quarters
2 whole cloves
3 whole peppercorns, crushed
3/4 teaspoon salt
1 cup heavy cream
4 tablespoons butter or olive oil*
3 tablespoons regular potato starch (not RS) for thickening
1/2 teaspoon or more Bob’s Red Mill raw potato starch, added just before serving**
2 tablespoons chopped fresh chives
Additional salt and pepper to taste
Crumbled crisp bacon, grated cheese, and a sprig of thyme for garnish, if desired.

Place the broth in a medium saucepan with the bay leaf, celery, onion, cloves, peppercorns, and salt. Simmer for 15 minutes. Remove from the heat and stir in the cream. Return to the burner and heat just to a simmer; remove the pan from the heat  and let stand, covered, for 5 minutes.

In another saucepan, melt the butter, if using, on low heat. If using olive oil, add it and the regular potato flour to the pan. Cook, stirring, for a minute or so, but do not let it brown. Remove the pan from the heat. Strain the warm cream mixture and add it slowly while stirring to the pan containing the fat and potato flour. Place the pan back on the heat and simmer for 5 minutes or until mixture is thickened, stirring frequently. Add additional salt and white pepper to taste.

Cover and simmer 20 minutes. Let cool until just warm or refrigerate until cold. Stir in raw potato starch just before serving. Stir often as starch may settle out on standing. Thin soup with a little extra broth if it is too thick after adding RS.

Makes about 3 servings of 1 cup.

Nutrition Data for soup only:
Calories: 447; Fat: 45g; Protein: 2.5g; Total Carbs: 10.6g; Fiber: 0.6g; Net Carbs: 10g***

*Use a liquid oil, such as MCT oil, if soup will be served chilled.

**The counts do not include the RS since the amounts will vary. It will have no carbs because it is all fiber, but the fats produced when it is fermented in the digestive tract will add a few calories. 

***The regular potato flour in the base, used to thicken it, will contain a some resistant starch if it is only heated once and then cooled, making the carbs lower than the nutrition data shows.

For more info on RS: 

Mark Sisson’s, The Definitive Guide to Resistant Starch is here: 

Dr. Andreas Eenfeldt:

Richard Nikoley probably has more information about RS than anyone, with 90 posts on the subject, His Resistant Starch Primer for Newbies is here.

Tom Naughton’s take is here:
Part 1
and here:
Part 2

Dr. Norman Robillard suggested caution when using RS in his first post, especially for anyone who suffers from small intestinal bacterial overgrowth (SIBO).
His followup post is a little more supportive:

Last, here’s a podcast from Jimmy Moore:

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(c) 2015, Judy Barnes Baker,

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Judy Barnes Baker

The working title for my first book was, “You’ll Never Know What You Are Missing.” It summed up my goal: to make eating for health synonymous with eating for pleasure. Once you discover the secret, you will find that the very best food for weight management, longevity, the treatment and prevention of disease, and over-all health and happiness is also the most sumptuous, satisfying, and indulgent way of eating the world has to offer. You are invited to the feast. Enjoy!
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f itoru
3 years ago

thanks for sharing your great blog. I appreciate all the information here.