What Are Resistant Starches? Meet The Blood Sugar-Friendly Carb
Fibers, carbs, starches… oh my! What’s the difference, and what do they do in the body? Well, let’s get into the nitty-gritty details of a specific carbohydrate we could all use more of: Resistant starches.
What are resistant starches?
Resistant starches are carbohydrates made of long chains of glucose that “resist” digestion in the small intestine.
Because they aren’t fully digested, they reach the colon intact where gut microbes ferment them. During this fermentation process, bacteria produce compounds called short-chain fatty acids or SCFAs (including butyrate) which play an important role in gut health. Therefore, resistant starches are prebiotics.
And this is where they start to sound eerily similar to fiber. However, fiber is a mix of plant cell-wall components like cellulose, pectins, and gums that humans can’t digest. Fiber is not a starch because it’s not made of glucose.
However, both resistant starches and soluble fibers can have prebiotic properties1.
RELATED READ: The 5 Best Prebiotic Supplements For Better Gut Health
Health benefits of resistant starches
Research suggests that increasing resistant starch intake may support several aspects of metabolic and digestive health.
- Improved insulin sensitivity: Some studies show resistant starch can help the body respond more effectively to insulin2, the hormone that helps lower blood sugar levels.
- A “second-meal” blood sugar effect: In some studies, eating resistant starch at breakfast helped improve blood sugar responses at lunch, even when the lunch meal itself didn’t contain resistant starch.
- Support for colon health: Short-chain fatty acids (especially butyrate) play a role in maintaining a healthy colon and may help regulate inflammation in the large intestine.
What foods are rich in resistant starches?
Under-ripe bananas, legumes (lentils, beans), whole grains (oats, barley), and raw potato starch are all sources of resistant starch. But types and sources of resistant starch can be further classified into five categories.
- Type 1: In these foods, the resistant starch is physically trapped inside plant cell walls, making it difficult for digestive enzymes to access. You’ll find it in foods like whole grains, seeds, and legumes.
- Type 2: These are the starches that occur naturally in some raw foods (including green bananas and raw potatoes).
- Type 3: This refers to the type of resistant starch formed when certain foods are cooked then cooled, a process known as retrogradation. Cooking and cooling these carbs is the best way to increase resistant starch in foods like potatoes, rice, pasta, beans, and lentils.
- Type 4: This is resistant starch that has been chemically modified during food processing to make it harder to digest.
- Type 5 forms when starch molecules bind with fats during cooking, creating structures that digestion enzymes struggle to break down. Here’s the best way to cook rice using this principle.
A case for leftover carbs
Truly, the easiest way to eat more resistant starches (and most of us would benefit from doing so) is to always cool your cooked starch before eating it.
When starchy foods (like rice, beans, and potatoes) are cooked, their starch granules gelatinize, making them easier to digest. When those foods cool down, some of the starch molecules reorganize and form resistant starch. It’ll help make those carbs even more blood sugar friendly, while making meal prep for the next few days even easier!
The takeaway
Resistant starches are a unique type of carbohydrate that come with impressive health benefits (like blood sugar balance and prebiotic effects). All you have to do to increase your intake is to cool your cooked starches before eating them.