Most of the starch you eat comes from carbohydrates. However, some types are resistant to digestion and are called resistant starch. Resistant starch is not digested by the stomach or small intestine and makes its way to the colon, mostly intact. Instead, similar to insoluble fiber, they pass through most of the digestive system, usually fermenting in the colon. Resistant starches fall under the category of prebiotics, or indigestible carbohydrates that help feed the good bacteria in our gut.
Resistant starch benefits
By assisting the body in increasing its production of short-chain fatty acids (made when beneficial gut bacteria break down dietary fiber as it travels through your digestive tract), resistant starches help create an environment where beneficial bacteria thrive.
Because it resists digestion, it is less likely to cause glucose or insulin spikes (yay for gradual glucose curves!). Several studies have shown that RS may improve insulin sensitivity and decrease blood glucose levels in response to meals.
RS has been shown to exert a “second meal effect.” This means that not only does RS beneficially decrease the blood glucose response at the time it’s consumed, but somewhat surprisingly, blood glucose and insulin levels also rise less than would otherwise be expected with the subsequent meal.
RS may help keep you fuller for longer .
Resistant starch sources
Some common food sources of RS include green (unripe) bananas, plantains, cooked and cooled rice, and cooked and cooled potatoes.
If you are on a low-carbohydrate diet or don’t tolerate those foods well, you can add RS to your diet without adding digestible carbohydrates. Bob’s Red Mill Unmodified Potato Starch (NOT potato flour) is one of the best sources of RS, with approximately eight grams of RS in one tablespoon. Potato starch is generally well tolerated, even by those who react adversely to nightshades.
There are three natural types of resistant starch:
Practical ways to try out resistant starch:
After cooking starches (potatoes, rice, etc.)
Heat back up (optional)
This process creates resistant starch.
Have a ripe banana with or without nut butter for a meal/snack on day one, and observe your glucose response.
The next day, try a green banana with or without nut butter for the same meal/snack and observe your glucose response.
Here is John’s Hopkins page for more info on resistant starch.