What Are Resistant Starches?

Photo from Gutmicrobiotaforhealth.com by ESNM

Resistant starch (RS) is a form of carbohydrate that is not digested in the small intestine so it travels to the large intestine. RS is a form of fiber which feeds the microbiota in our large intestines.

 Bananas, potatoes, legumes and grains are foods that have natural resistant starches in them. These foods support the environment of healthy bacteria in the large intestine. It has been suggested that resistant starch can support gut health and enhance satiety via increased production of short chain fatty acids (SCFAs). The SCFAs produced by bacterial fermentation and produce butyrate, proprionate, and acetate for fuel. This helps with the stimulation of blood for a healthy gut as well as increase tone and reverse the shrinking of cells that happen with low fiber diets. The SCFAs also lower the pH of the feces another signal of colonic health.  

Resistant starch is just another good reason to eat more fruits and veggies especially bananas, potatoes, legumes (beans) and grains.

EXTRA INFO: There are several types of resistant starch and they are classified according to structure or source :

TABLE 1. Resistant Starch Classifications

• RS1 is physically inaccessible to digestive enzymes. Its sources include whole or partially milled grains, seeds, and legumes.

• RS2 resists digestion because of the granule’s nature. Sources include raw potatoes, underripe bananas, some legumes, and high-amylose starches, such as high-amylose corn.

• RS3 is produced in the cooking-cooling process. Sources include bread, tortillas, cooked and cooled potatoes, rice, and pasta.

• RS4 is a chemically modified starch found in a wide range of products.


Weisenberger, J.,m Resistant Starch — This Type of Fiber Can Improve Weight Control and Insulin SensitivityToday’s Dietitian, September 2012 Issue