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Resistant Starch: A Must for Paleo Eaters

Not All Starchy Carbs Are The Same:  Why it’s vital to include resistant starch in a paleo diet.


So what is resistant starch (RS) anyway?

Most starches are absorbed quickly in the small intestine, causing a rise in blood sugar and a spike in insulin production. Resistant starch (RS) resists digestion, arriving at the colon largely unabsorbed. RS has little to no effect on blood sugar and insulin production. Our bodies react to it, and treat it, like soluble fiber, rather than like carbohydrate.  RS that makes its way to the colon feeds the beneficial bacteria that live in our colon.


        4 Types of Resistant Starch:


          -RS1 Physically resists digestion due to a strong outer matrix. Found in seeds, legumes and unprocessed whole grains.

          -RS2 – Occurs naturally in granular form. Found in raw white potatoes, unmodified potato starch (uncooked), green under-ripe bananas, banana flour (uncooked), plantains (uncooked) and high amylose corn.

          -RS3 – Retrograded starch that is formed when starchy foods are cooked then cooled down. Examples high in RS3: white rice (highest of which are parboiled and Basmati), white potatoes, pasta made from rice or potatoes, and legumes. Even if these starches are again reheated after cooling down, the RS3 starch remains intact or even increases. Subsequent cooling after reheating increases the RS3, so “leftovers” are a good source.

           -RS4 – Not found in nature. Chemically modified starches which are often added back into refined white flours to increase their fiber content.


So resistant starch (RS) is just a type of fiber?


It’s important to understand what type of fiber RS is.

There are two types of food fiber, insoluble fiber – doesn’t dissolve in water and isn’t fermented by colon bacteria, and soluble fiber – dissolves in water and is fermented in the colon. Insoluble fiber, increases the bulk of our stools and helps us avoid constipation. It does nothing for the beneficial bacteria living in our colon. Soluble fiber (resistant starch), can cause amazing health-beneficial changes via our colon bacteria, as it is fermented.

During the fermentation process the bacteria produce many substances that our own body cannot including: certain vitamins, serotonin (95% of serotonin in the body is made by our gut bacteria), melatonin, butyrate and short chain fatty acids. It is these substances that improve our fat burning ability, enhance our mental clarity and mood, and enhance our nutritional level. Without this special soluble fiber/resistant starch, low-carb or “keto” eaters will often find their health, mood and performance decline over time. Muscle weakness, fatigue and depression may set in. This is ironic because their goals of ketosis, or near ketosis can still be maintained if they eat carbs in the form of resistant starch.


Why is resistant starch (RS) so important on a paleo diet?


Those following a paleo diet, who avoid grains and legumes, while eating a large variety of vegetables, fruits, and protein, can inadvertently eat far too little soluble fiber. This means the beneficial bacteria of the colon, our microbiota, will begin to starve and die off. If we lose too many of these potent defenders of our health and immune system, all the benefits listed below, that our microbiota impart to our bodies, may start to disappear.


What are the health benefits of resistant starch (RS)?


  • Potential strengthening of the bowel wall and decrease of incidents of bowel disease such as: diverticulosis, IBS, Chron’s, ulcerative colitis and colon cancer.
  • Potential to improve blood sugar levels and insulin regulation, not only during the meal containing the RS, but continuing on into the next meal (called the second meal effect).
  • Potential improvement in mental health, depression/anxiety, and mood disorders.
  • Potential decrease in lipid oxidation and decrease in fat accumulation.
  • Potential improvement in cholesterol and lipid profiles.
  • Improved sense of fullness and satiation after eating.
  • Strengthening of the immune system.
  • Break down of toxins and carcinogens.
  • Powerful anti-inflammatory effects throughout the body.
  • Protection from colonization of harmful bacteria, such as C. Diff.


What are good sources of resistant starch on a paleo diet?


  • White rice – That has been cooked (with a TBS. of coconut, or other oil is even better), then cooled overnight in the fridge. If reheated after being cooled down, the resistant starch that formed in the rice maintains its resistant quality, even when heated up again. Parboiled and Basmati varieties contain the most.
  • White potatoes – Raw, or cooked, then cooled, then eaten cold or reheated. Just as with the rice, when the cooled potatoes are reheated, significant resistant starch remains. (Best avoided by those who have arthritic pain reactions to nightshades.)
  • Green bananas and banana flour – Eaten before perfect ripeness, the greener the banana peel the higher the RS content. Flour must not be heated. It tastes good sprinkled in smoothies.
  • Pasta made from rice or potato flour – Cooked, cooled overnight, then reheated. The pasta will actually increase its resistant starch content each time it is reheated.
  • Unmodified potato starch – Eaten without being heated above 140°F. Either mixed in a beverage, or mixed into other foods or smoothies which are less than 140° in temperature. Caution: use only in small amounts, such as 1 tsp. or less. Otherwise, you may experience bloating and gas. (Again, avoid if nightshades trigger arthritic pain, as potatoes are nightshades.)
  • Others – These contain RS, but in much lower quantities than the items listed above: rice cereal, carrots, yam, sweet potato, rutabaga, turnip, parsnip, beets, squash, mushrooms, avocado, apple, mango, papaya.


A whole new understanding of how our “gut bugs” (microbiota) keep us healthy.


One of the most staggering new health discoveries of the last decade is how our body’s function, health and immune response is directly tied to our microbiota. Of the entire number of cells alive in our body, only 10% are actually human. The other 90% of living cells are the microbes that coexist on, and inside our bodies. We live in a symbiotic relationship with them, if our microbiome is healthy, then we are healthy, and vice versa.

If we think of our microbiota as pets (that live inside us), we can think of resistant starch as the special pet food that we must eat, for those special RS foods to reach our colon to feed our “pets”. Too little RS “pet food” and our “pets” die off, leaving us vulnerable to a host of physical and mental health problems, from which they were designed to protect us.

Therefore, when choosing our food intake, we must not only think what sounds appealing and healthy for us to taste and eat, but what will be most helpful and beneficial to our coexistants, our “internal pets” – our microbiota.




Comprehensive Reviews in Food Science and Food Safety