What is “Resistant Starch”?

By Henry Gould – June 11th, 2019

The last few years have seen a huge uptick in a number of health and wellness trends, including stuff like ketogenic diets, fermented foods, intermittent fasting and High Intensity Interval Training (HIIT). Some we’ve covered on this blog before; others like intermittent fasting seem worthy of a longer discussion in the future.

One item that seems to have somewhat missed the “health buzz word” news cycle is something called Resistant Starch (RS). RS, as will be explained below, is a longer chain, less digestible form of starch (i.e. sugar) that is not as easily turned to glucose in the body, thus keep your blood sugar and insulin levels lower while still allowing for a feeling of fullness, a production of short-chain fatty acids, and other nutritional benefits.

I found it particularly interesting because many times when we think of the food we’re planning to eat, “carbs” all get lumped into the same negative pile. In reality they can have vast differences in terms of their effect on our body. A bag of skittles and a boiled potato are both technically carbs; both contain sugar, but one is going to have a much different impact on your health.

Let’s dive a a little deeper…

What is Resistant Starch (RS)?

RS is a form of starch (starch = large chain of glucose molecules) that is not digestible – resistant – in the stomach, or digestible only in certain forms (RS1, RS2, RS3).

What foods do you find RS in?

RS is found in many foods, however the temperature of the food can also play a factor in how much RS is available. For example, a cooked and cooled potato will contain more RS than a hot boiled potato, as the RS molecules have had a chance to consolidate and reform. When the food is hot, they denature and break apart, thus becoming easier to digest, and subsequently more glucose is available in the body.

Foods that are high in RS include oats, potatoes, legumes / beans, grains, green bananas, and cooked and cooled rice. As mentioned above, all these foods generally have more RS once cooked and cooled, or not cooked at all.

Why is RS good for you?

Despite what you might hear from strict followers of ketogenic or carnivore diets, the human body needs glucose to function. Typically that glucose comes in the form of fruits, vegetables and grains. All these items contain differing amounts of glucose, some in very simple forms (i.e. sugar in an apple), others are in longer chain, more complex forms (i.e. the RS in a potato).

RS is a chain of starch so long that is either not able to be digested, or can only be digested by gut bacteria fermentation. If it’s completely undigestible, the RS will pass through the body similar to fiber, thus helping to create regularity in the digestion which has its own positive effects on the body. It can also lead to a feeling of fullness without severely impacting the blood sugar. This can be particularly useful if one is trying to lose or maintain weight, but has a hard time feeling full after a meal. Many times we eat a healthy dinner (salad + protein) only to feel hungry an hour later, thus becoming prone to snacking on less healthy things, or just overeating entirely. If a small amount of cooked and cooled chickpeas are added to the same salad, the feeling of fullness is much greater without sacrificing an increase in bad carbs.

Since some types of RS are fermented by our intestinal bacteria, which can lead to the production of many beneficial compounds including short-chain fatty acids and butyrate. These and other compounds have a variety of benefits to the body including the promotions of healthy colon, lowered risk of colon cancer, as well as increased absorption and production of vitamins.

Some people have taken it to the very extreme, putting scoops of potato starch in water and drinking it on a daily basis. By all means try that out (it sounds disgusting!) but overall, eating a variety of fruits, vegetables and grains will likely help increase your RS levels.


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