Resistant starch: types, benefits & food sources
Resistant starch is starch that resists digestion in the small intestine and ferments in the colon like a dietary fiber. It acts as a prebiotic — feeding beneficial gut bacteria and producing short-chain fatty acids — while adding fewer available carbohydrates than regular starch. This guide covers the four types, the benefits, the richest food sources, how much to have per day, and why green banana is a leading source of native RS2.
The four types of resistant starch
Resistant starch is grouped into four types by why it resists digestion. Green banana powder is RS2.
More on the RS2 mechanism on the science page.
Resistant starch benefits
Resistant starch is a prebiotic fiber: it ferments in the large intestine and produces short-chain fatty acids (SCFAs), especially butyrate, which feed colonocytes and beneficial bacteria.
Because it resists digestion in the small intestine, RS contributes fewer rapidly available carbohydrates than regular starch — a reason it is studied for low-GI diets.
RS is measured as part of total dietary fiber, helping products meet fiber targets without gums or bulking agents.
Resistant starch is studied for effects on fullness, post-meal blood sugar and metabolic markers.
Foods high in resistant starch
One of the richest natural sources of RS2. Prebyo's organic green banana powder tests at >56 g resistant starch per 100 g.
High in RS2 when raw; cooking gelatinizes and reduces it unless cooled again (then RS3).
Beans, lentils and peas carry RS1 within their cell structure.
Rice, pasta and potatoes form RS3 after cooking then cooling.
Provide RS1 locked in the intact grain matrix.
How much resistant starch per day?
Resistant-starch studies commonly use around 15–30 g per day. There is no official upper limit for resistant starch from food; increasing intake gradually helps the gut adjust to the added fermentable fiber. Individual needs vary — this is general information, not medical or dietary advice.
Resistant starch in F&B formulation
For manufacturers, native RS2 from green banana is attractive because it adds fiber and resistant starch with a neutral taste and pale color, low sugar, and a clean single-ingredient label — no chemical modification. It suits low-GI, high-fiber, gut-health and clean-label positioning across bakery, beverages, bars, cereals, supplements and dairy alternatives.
See the product specification and applications by industry, or compare RS2 vs inulin.
Resistant starch FAQ
What is resistant starch?
Resistant starch is starch that resists digestion in the small intestine and passes to the large intestine, where it ferments like a dietary fiber. Because it isn't broken down into glucose in the upper gut, it adds fewer available carbohydrates and acts as a prebiotic, feeding beneficial gut bacteria.
What are the types of resistant starch?
There are four types: RS1 (physically trapped in whole grains, seeds and legumes), RS2 (native granular starch in green banana and raw potato), RS3 (retrograded starch formed when cooked starch is cooled), and RS4 (chemically modified starch). Green banana powder is RS2 — native and not chemically modified.
What are the benefits of resistant starch?
Resistant starch acts as a prebiotic fiber that ferments in the colon and produces short-chain fatty acids such as butyrate, supports a lower glycemic response because it resists digestion, and counts toward total dietary fiber. It is also studied for satiety and metabolic markers.
Which foods are highest in resistant starch?
Green (unripe) bananas and green banana powder are among the richest sources of RS2. Others include raw potato and potato starch, legumes, cooked-and-cooled rice, pasta and potatoes (RS3), and whole grains and seeds (RS1).
How much resistant starch should you have per day?
Studies on resistant starch commonly use around 15–30 g per day. There is no official upper limit for resistant starch from food; most people increase intake gradually so the gut can adjust. This is general information, not medical advice.
Does cooking destroy resistant starch?
Heat and moisture gelatinize native RS2, reducing resistant-starch content, which is why green banana powder retains the most RS2 in no-bake or low-heat uses (below ~140°F / 60°C). Cooling cooked starch can form a different type, RS3.
Is resistant starch the same as fiber?
Resistant starch behaves like a soluble, fermentable dietary fiber and is measured as part of total dietary fiber, but it is a specific category of starch rather than a traditional structural fiber like cellulose.