What is Resistant Starch & Why is it so Good For You?

With the increasing trend of low-carb diets, the surge in interest in Resistant Starch foods and supplements might come as a surprise. So, what’s the buzz around Resistant Starch, and why is it gaining traction?

Resistant Starch, true to its name, is a specific kind of starch made up of extensive glucose chains. While it’s present in a variety of foods like grains, potatoes, and certain fruits and vegetables, its uniqueness lies in its digestion process. Unlike the majority of starchy foods that get broken down into sugars in our small intestines and swiftly enter our bloodstream, Resistant Starch challenges this norm. It bypasses regular digestion, traveling intact to our colon, where it acts much like soluble fiber.

Historically, along with plant fiber, Resistant Starch was a predominant component of our meals. However, modern food processing methods, especially for cereals, grains, and starchy vegetables, have considerably reduced their presence in our diets.

Why is Resistant Starch So Special?

1. It feeds our ‘Good’ gut bacteria

Resistant starch behaves in a similar way to soluble fiber – when it reaches our colon at the end of our large intestine it feeds our friendly gut bacteria – where it is fermented and broken down into short-chain fatty acids – such as butyrate resulting in some unique health benefits. It also has several beneficial effects on the colon.

By feeding and helping our good gut bacteria thrive – RS helps to promote a balanced gut -and increases the diversity of gut bacteria – which in turn helps control the growth of pathogens and undesirable strains and species of bacteria associated with obesity, diabetes, and chronic disease.

2. It helps us stay lean

We extract less energy from raw and unprocessed foods through digestion than we do from refined and processed foods – so while a plate of wholegrain and a plate of processed foods may contain the same amount of calories, we digest and absorb fewer of the available calories from whole foods than we would from processed & refined foods.

As Resistant Starch is only partly digested, we typically extract half the number of calories of energy per gram than we do from other carbohydrates. What is more foods high in resistant starches tend to fill us up more quickly leading us to eat less.

3. It increases insulin sensitivity

RS doesn’t digest into blood sugar, which means our bodies don’t release much insulin in response.

RS might also improve insulin sensitivity via alterations in fatty acid flux between muscle and fat cells. Some data indicate that ghrelin might increase with RS consumption, improving insulin sensitivity. RS may also lower blood fats, which also improves insulin sensitivity.

Several studies show that it can improve insulin sensitivity, as in how well the body’s cells respond to insulin (24). Resistant starch is also very effective at lowering blood sugar levels after meals.

It also has a “second meal effect” – meaning that if you eat resistant starch with breakfast, it will also lower the blood sugar spike at lunch. The effect on glucose and insulin metabolism is very impressive. Some studies have found a 33-50% improvement in insulin sensitivity after 4 weeks of consuming 15-30 grams per day.

The importance of insulin sensitivity cannot be stressed enough. Having low insulin sensitivity (insulin resistance) is believed to be a major causal factor in some of the world’s most serious diseases, including metabolic syndrome, type 2 diabetes, obesity, cardiovascular disease, and Alzheimer’s Disease. By improving insulin sensitivity and lowering blood sugar, resistant starch may help you avoid chronic disease and may make you live both longer and better.

4. It helps lower blood cholesterol

RS may help to lower blood cholesterol and fats, while also decreasing the production of new fat cells (the latter has only been shown in rats). Also, since SCFAs can inhibit the breakdown of carbohydrates in the liver, RS can increase the amount of fat we use for energy.

5. It helps to treat leaky gut and irritable bowel syndrome

Butyrate and other short-chain fatty acids produced by the fermentation of Resistant Starch in the colon have a remarkable effect on reducing intestinal permeability or ‘leaky gut’ and resulting symptoms of IBS and ulcerative colitis. Butyrate and other short-chain fatty acids play an important role in keeping our gut wall healthy and preventing unwanted pathogens or particles from passing into our bloodstream – which is associated with inflammation, autoimmune responses, and many diseases, including fatty liver, heart failure and autoimmune diseases such as allergies, asthma, MS and Parkinson’s to name a few.

6. It helps reduce the risk of Colon Cancer

It reduces the pH level, potently reduces inflammation and intestinal permeability (leaky gut) leads to several beneficial changes that should lower the risk of colorectal cancer, which is the 4th most common cause of cancer death worldwide

What are the different types of Resistant Starch

Not all resistant starches are the same. There are 4 different types of resistant starch. The preparation method has a major effect on the ultimate amount of resistant starch in food.

For example, allowing a banana to ripen (turn yellow) will degrade the resistant starches and turn them into regular starches.

  • Type 1
    Found in grains, seeds, and legumes and resists digestion because it is bound within the fibrous cell walls. Cannot be broken down by digestive enzymes
  • Type 2
    Intrinsically resistant to digestion and contains high amounts of amylose. Found in: fruits, potatoes, hi-maize RS products, corn, and some legumes. Note: The more “raw” or “uncooked” a food is, the more RS it tends to have, since heat results in the gelatinization of starch – making it more accessible to digestion.
  • Type 3
    In contrast to Type 2 Resistant Starches, Type 3 RS can be created when certain starchy foods such as pasta, potatoes, and rice are cooked and cooled. Through this process the starch changes in composition, increasing its resistance to digestion. Studies have found that even when reheating previously cooked starchy foods the composition of resistant starch increases
  • Type 4
    Companies have isolated RS (usually from corn) to include it in processed foods (e.g., breads, crackers, etc.).This is not naturally occurring RS — it’s produced mostly via chemical modification, and it’s found in synthetic and commercialized RS products, such as “Hi-Maize Resistant Starch”.

How much Resistant Starch should you consume?

Resistant Starch is considered safe and recommended for consumption of up to 40-45 grams per day. More than this may result in discomfort or bloating, if your body and gut bacteria are not in such quantities/

How we respond to RS varies by the type. One might notice more side effects when consuming RS3 (versus RS1, RS2, and RS4). Our ability to ferment RS can increase over time, making it possible to adapt to a higher RS intake.

RS seems to be tolerated best when:

  • It’s in solid food form (rather than liquid)
  • It’s consumed as part of a mixed meal (rather than alone)
  • Consumption is increased gradually over time (rather than a lot at once)

What are the best sources of Resistant Starch?

Here’s an idea of how much RS is found in common foods. Note: These are average values and will vary.

Resistant Starch content of commonly consumed foods


Can Resistant Starch improve mental health?

Emerging research suggests a gut-brain connection. Since RS positively impacts gut health, it might indirectly benefit mental well-being by promoting a healthy gut microbiome, which has been linked to mood regulation.

Is Resistant Starch safe for people with IBS or other digestive disorders?

While RS can benefit many individuals, those with IBS or other digestive disorders should approach it with caution. It’s essential to introduce RS slowly and monitor symptoms, as it can exacerbate certain conditions.

Does freezing food affect its Resistant Starch content?

Similar to the process of cooking and cooling, freezing can also increase the RS content in certain foods due to the crystallization of starch molecules.

How does Resistant Starch impact the absorption of minerals and other nutrients?

RS can enhance the absorption of certain minerals, especially magnesium and calcium, in the colon. This is due to the fermentation process and the production of short-chain fatty acids.

Are there any foods that naturally have a higher Resistant Starch content when cooked vs. raw?

Yes, foods like potatoes and rice increase in RS content when cooked and then cooled, as opposed to their raw counterparts.

Final Words

Processed and cooked carbohydrate-rich foods lead to higher energy (calorie) absorption. When machines and ovens pre-digest these foods, we’re left with starches that are easily digestible. This isn’t ideal for maintaining blood sugar levels, achieving a lean physique, or promoting gut health.

Historically, many cultures have maintained good health and a lean stature by consuming unprocessed legumes, whole grains, and starchy vegetables. Resistant Starch (RS) might play a role in this.

Benefits can potentially be observed with an intake of just 6-12 grams/day of RS. However, aiming for around 20 grams/day, primarily from whole plant foods, could be optimal.

Intakes exceeding 40 grams/day, especially from industrially produced RS products, might lead to digestive issues. Moreover, the benefits derived from industrially processed RS might not be as pronounced as those from natural whole foods.