About resistant starch

About resistant starch explains where it is found and why it is so good for us.

Plant starches are found in many foods like potatoes and grains such as oats and wheat, and in smaller amounts in legumes. They contain two different compounds; amylose makes up about a quarter.

Amylopectin makes up the other three-quarters. 

They are quite different. Amylose is long chain of glucose molecules linked together in what are known as polysaccharides; the number of sugar units varies from hundreds and can be several thousand, depending on the source of the starch.

In amylose this long chain has a twisted or helical configuration that makes it difficult for enzymes to reach the glucose units; it is less digestible and more of the food tends to reach the large intestine for breakdown by the normal flora instead. It is less likely to raise your blood-sugar dramatically.

Potatoes grown in compost

This page was last updated by Bernard Preston on 26th March, 2021.

New potatoes interestingly, as compared to those from cold storage are also more resistant to the enzymes in the small intestine, much passing through to the large bowel where friendly short-chain fatty acids are produced instead of glucose. They have a profoundly good effect on our immune systems, and supply energy to the cells lining the gut.

Amylopectin, the three-quarters fraction of starch, is soluble in water; it, on the other hand, consists of short, highly branched chains which are readily digested by enzymes in the mouth and small intestine.

Then the many thousands of glucose molecules are ready for immediate absorption, and cause a rapid rise in blood-sugar. This puts a huge strain on the liver which has to suck up all this carbohydrate that one has just eaten.

In medical terms it is called chronic excessive carbohydrate consumption; it is the true cause of obesity particularly if it is mainly refined starch, or has a high amylopectin fraction.

That is excellent if you are an athlete, but not if you sit behind a computer for most of the day.

After about two decades there is great risk of developing type 2 diabetes and non-alcoholic steatohepatitis; fibrosis of the tissue caused by fatty liver disease.

This is complex stuff, but bear with me if you want to be able to enjoy more energy, and in particular if you are obese and tired of the loss of well-being that goes with it.

Three types of starch

  • Rapidly digested starch
  • Slowly digested starch
  • Resistant starch

The colossal problem with the modern Western food is that it consists in the main of rapidly digested starch; examples would be boiled potato, french fries and short-grain, precooked rice. They have a strongly glycemic effect, read a very high GI. They are rich in amylopectin; they spike your blood glucose.

Do note that new potatoes do not fall into this category, but they are hard to get unless you grow them yourself; they must not have come out of cold storage.

Commercial potatoes are also sprayed with toxic herbicides like paraquat just before reaping to kill off the haulm; we recommend growing them yourself if you have a large enough garden.

Resistant starch on the other hand is not absorbed in the small intestine as it is high in the helical amylose, which enzymes find more difficult to digest. It reaches the colon where it is fermented by the microflora which are able to break down these foods which are then absorbed more slowly in the large intestine, not as glucose, but as nutritious short-chain fatty acids.

These bacteria and yeasts also produce various gases which cause flatulence which is quite normal, and to be expected; to put it crudely, people eating good food fart more.

In order for this to happen normally, a broad spectrum of the microflora is necessary. In fact researchers are finding that many of the diseases of our modern world have their origin in a deficiency of these supportive bugs in the colon.

One can take tablets called probiotics, but it is very easy to get them from your food. Just five minutes work every morning, easily done by one child, will provide your family with what is needed; read more about kefir benefits.

Oddly, one friend who started enjoying kefir daily reported much less gas passed.

About resistant starch

100 percent wholemeal

To sum up this page about resistant starch describes how some carbohydrates are broken down in the small intestine giving an immediate and unwelcome surge in blood glucose, but others pass through to the colon for fermentation.

In the colon, often called the large intestine, they are acted upon by these wonderful bacteria, or the normal flora, that live there specifically to digest this resistant starch and turn it into various fatty acids like butyrate; google this substance as it acts as a very important anti-inflammatory in the body.

Those profoundly good bugs that live in your colon incidentally are called probiotics; in order to flourish they need plenty of resistant starch that has escaped the attention of the enzymes in the small intestine.

In modern lingo, that carbohydrate, along with indigestible fibre, reaches the colon where it is known as a prebiotic; there it is fed upon and turned not into glucose but short chain fatty acids.

The beauty of resistant starch is that it reduces the risk of getting type-2 diabetes, and in fact ameliorates the effect of the disease. This is because it does not cause the surge in blood sugar, demanding an immediate spurt of insulin which stores that glucose as adipose.

That is what happens to rapidly digested starch.

Interesting research shows that soluble fibre found in rolled oats, for example, has a greater effect on the insulin spike, whereas resistant starch reduces the glucose; they work together producing a wonderful beneficial effect[1].

It is also because of that butyrate which has an anti-inflammatory effect on your pancreas too, helping to prevent autoimmune diseases like diabetes. Don't take it in tabulate form but rather let your food be your medicine. If you know about resistant starch, the friendly bugs in your colon will produce plenty of it for free.

So how do we get more resistant starch onto our plates?

It comes as no surprise that the more food manufacturers process our grains and potatoes, the greater the amount of rapidly digested starch it will contain.

Whole grain, unprocessed wheat contains 14% of resistant starch that will reach the colon, whilst refined cake flour has 2 percent or less, and is rapidly absorbed, spiking the blood sugar.

My own experimentation shows that even wholesome 100% full grain bread still gives a surge in my blood glucose to unacceptably high levels, even with just butter. Eaten with a salad that is another matter; it is much lessened. But this sharp rise can also be completely countered by a short ten-minute walk after lunch.

That is because 86% of the starch even in true wholemeal bread is still made up of unresistant carbohydrate; it turns to sugar so you must burn it, or you'll finds pounds being layered on in the wrong places.

Over and above whole grains, legumes like peas and beans, and seeds such sunflower and flax have a large amount of resistant starch; the enzymes in the small intestine have greater difficulty getting to the carbohydrate in unrefined foods.

These are what as known as prebiotics. Don't fall prey to supplement companies  and spend a fortune buying them in capsules; just eat more unrefined foods.

And let them cool first, preferably overnight in the fridge for tomorrow's dinner.


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Cooling is the other way to reduce the rapidly absorbed fraction; boiled potato is very quickly digested in the small intestine, spiking blood sugar and demanding a spurt of insulin, immediately depositing the glucose in all the wrong places. It makes us fat.

But take that boiled potato, cool it overnight and then enjoy it, hot or cold, and far more of it reaches the colon for fermentation; knowing about resistant starch has profound implications for the good housewife.

Add some vinegar or fresh lemon juice and you make your chilled potato-salad even more resistant to digestion in the small intestine.

A cup of rolled, raw oats has 17.6g of resistant starch which would pass through to the colon. Food manufacturers grind it finely, remove much of the bran and precook it, reducing that whole grain into porridge containing only 0.5g; most of it is instead digested in the small intestine producing glucose.

Look out for the cooking time on the package. A pasta, oats or rice that requires long boiling will have far more resistant starch in it. Avoid the precooked stuff; it makes you fat because it's easily acted on by enzymes in the small intestine and rapidly absorbed into the blood-stream.

Elsewhere we'll look at new potatoes that have far more resistant starch in them.


The fibre in our food is also a polysaccharide but our bodies do not secrete the enzymes necessary to digest it; it passes through the small intestine unchanged. Some of it is broken down in the colon by the microbiome producing very important short-chain fatty acids. It is often called a pre-biotic, food for the teeming billions of bacteria and yeasts in the large bowel[4].

Fibre is also called the 'non-starch' component of our food. Pectin is an example, familiar to every jam-maker.

Understanding how net carbs work will be a big part of your progress in dealing with obesity.

Rolled oats

Unprocessed rolled oats is one of the best examples describing about resistant starch; the finest remedy for high cholesterol. It's also an excellent solution to insulin resistance; it hardly affects the postprandial blood glucose, especially if you take a short walk after breakfast.

These Quaker oats recipes should be a basic on everyone's shopping list. They are the kinds of meals that grandma would have offered, and are still the best; but not the refined stuff that comes in a box.

In short, large prospective studies prove that a higher whole-grain consumption reduces the risk of death from chronic diseases such as type 2 diabetes and cardiovascular disease.[2]

On other hand refined grains increase the risk of diabetes and cardiovascular disease because they make you fat.


Sprouting chickpeas in an inverted bottle.

Legumes like chickpeas and beans have large amounts of resistant fibre, but they need to be soaked, rinsed several times and preferably sprouted and even fermented to remove so-called anti-nutrients.

As soon as you start investigating the subject about resistant starch, you begin to realise it is profoundly complex. When you buy legumes like chickpeas in a can, you have no idea how they have been prepared; certainly they would not have been sprouted or fermented, but probably not soaked and rinsed adequately either. It is important to get the lectins out.

Rinsing and soaking several times can be done overnight, followed by another three days of sprouting chickpeas; the actual time taken is perhaps fifteen-minutes to give you enough for homemade hummus for a month; not a lot.

Cooking chickpeas is not difficult, but it does take some time which is why we should prepare several pounds at a time and freeze them.

It is a lot simpler with a pressure-cooker.


There is a profound body of research now showing that the beneficial bacteria and yeasts in the gut have an enormous influence not only on our immune system but also on distant organs like the brain, lungs and skin.

Rural children enjoying food high in plant starches, legumes for amino-acids and less red meat have four times the level of beneficial short chain fatty acids, as compared to Western kids whose meals consist predominantly of animal protein, sugar and refined carbohydrate, fat and low in fibre, due to the change in the populations in their alimentary canals.

That production of SCFA lowers the pH in the gut makes it less hospitable to pathogens like E. coli.

These SCFA are of three types; acetate, proprionate and butyrate. The names are not important but their function certainly is. Since they circulate throughout the whole body, via the immune system they give us protection against an unwanted inflammatory response in all organs; hence their profound influence on the brain and lungs, for example.

These SCFAs also provide up to 10% of our caloric requirements with no insulin response; hence the role they play in metabolic disorders like obesity and diabetes[3].

Ketogenic diets

Learning about resistant starch, truly grasping it and incorporating into your meal planning, will mean that you will most likely not have to get thinking about the ketogenic diets, or far worse still those where you have to count calories.

Starches are important nutrients but food companies mess them up so badly that they make us obese and diabetic. Grasp the nettle, prickly though it may be, totally cut out the refined carbs and manage the others correctly and need have no fear of them, or the serious loss of wellness that they cause to so many.

Short cuts

There are no short cuts much to our dismay, to well-being. What is astonishing is that so desperate are some to shed unwanted pounds, but equally determined not to alter their lifestyle, that they would risk the serious side effects of sibutramine and amphetamines, for example, in some weight-loss products rather than change to finding out about resistant starch.

Worse, these products and drugs are very expensive. Beware if you value your life.

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  1. Consumption of both resistant starch and beta-glucan improves postprandial plasma glucose and insulin in women.
  2. Association between whole grain intake and risk of mortality: two large prospective studies in US men and women.
  3. Food, Microbiota and Gut-Lung Connection
  4. Food Polysaccharides. Web: http://www.vivo.colostate.edu/hbooks/pathphys/digestion/basics/polysac.html

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