Resistant Starch: What It Is, How to Increase It, and Why It Matters

I first became interested in resistant starch while following an anti-inflammatory diet. As I started planning meals and cooking more beans, potatoes, rice, and lentils, I discovered that simply cooling these foods could make them even more beneficial. That inspired me to dig deeper into the science—and share what I've learned with you.

What Is Resistant Starch?

This is a type of carbohydrate that isn't fully digested in the small intestine. Instead, it reaches the large intestine, where it feeds beneficial gut bacteria.

As these bacteria ferment it, they produce short-chain fatty acids like butyrate, which help support gut and colon health.

Think of resistant starch as a carbohydrate that behaves more like dietary fiber than regular starch.

Types of Resistant Starch

There are four types of it, but the first three are the ones you're most likely to encounter in everyday foods.

RS1 – Naturally Protected

Found in whole grains, beans, lentils, and seeds, where the food's structure protects the starch from digestion.

RS2 – Naturally Resistant

Found naturally in foods like green bananas and raw potatoes. As these foods ripen or are cooked, much of this starch is lost.

RS3 – Retrograded Starch

This is the type you can easily create at home. When foods like potatoes, rice, or pasta are cooked and then cooled, part of their starch becomes resistant through a process called retrogradation. Much of it remains even after gentle reheating.

RS4 – Modified Resistant Starch

A manufactured form used in some processed foods. Since it isn't created through home cooking, it isn't covered in this guide. make at home, so it isn't the focus of this article.

Why Resistant Starch Is Good for You

How to Increase Resistant Starch Naturally

Fortunately, you don't need any special ingredients.

Does Reheating Destroy Resistant Starch?

Foods That Lose Resistant Starch

Some foods naturally lose it when cooked or ripened.

These include:

• Green bananas that become yellow
• Raw potatoes after cooking
• Freshly cooked rice (before cooling)
• Freshly cooked pasta
• Freshly cooked potatoes

Foods That Naturally Increase Resistant Starch (Quick Reference)

Food	Naturally Contains	More After Cooling?
Potatoes	⭐⭐	✅ Yes
Rice	⭐	✅ Yes
Pasta	⭐	✅ Yes
Beans	⭐⭐⭐	✅ Yes
Lentils	⭐⭐⭐	✅ Yes
Chickpeas	⭐⭐⭐	✅ Yes
Oats	⭐⭐	Overnight soaking
Green bananas	⭐⭐⭐	No (decreases as they ripen)

Why I Always Plan Ahead

I've gotten into the habit of cooking a little more than I need, especially when I'm making potatoes, rice, pasta, or beans. I started doing it years ago simply because it made busy weekdays so much easier. Knowing that part of tomorrow's meal is already waiting in the refrigerator is such a relief after a long day.

Later, I discovered that letting these foods cool overnight actually increases their resistant starch. It felt like a win-win. I wasn't changing the way I cooked or buying any special ingredients—I was simply getting more from foods I already loved.

These days, you'll almost always find a container of cooked beans, rice, potatoes, or pasta in my refrigerator. They become quick salads, hearty soups, easy side dishes, or simple lunches the next day. Meal planning doesn't have to be complicated. Sometimes it's as easy as cooking a little extra today, so tomorrow's meal is not only faster to prepare but also comes with the added benefits of it.

You May Also Like

• How to Make Homemade Kefir – Learn how to make probiotic-rich kefir at home to support a healthy gut microbiome.
• Anti-Inflammatory Diet: What to Eat for Better Health – Discover everyday foods and habits that may help reduce inflammation naturally.
• Bean Conversion Guide: Dried Beans to Cooked Beans – A handy guide for cooking beans, one of the best natural sources of it.
• How to Cook Dried Beans – Step-by-step instructions for perfectly cooked beans every time.

How I Researched This Article

For this article, I reviewed peer-reviewed research, trusted health organizations, and evidence-based nutrition resources to make sure the information is accurate, practical, and easy to understand.

• National Cancer Institute – Resistant Starch
• Resistant Starch: Promise for Improving Human Health - A comprehensive scientific review exploring the different types of resistant starch and their potential role in supporting the gut microbiome, digestive health, blood sugar regulation, obesity prevention, and overall metabolic health.
• Harvard T.H. Chan School of Public Health – The Nutrition Source
• Effects of Resistant Starch on Glycaemic Control: A Systematic Review and Meta-analysis: British Journal of Nutrition

FAQ

Is resistant starch the same as fiber?

Not exactly, but it behaves similarly because it isn't digested in the small intestine and helps nourish beneficial gut bacteria.

Does freezing affect resistant starch?

Freezing generally preserves resistant starch that has already formed after cooling.

Which food has the most resistant starch?

Cooked and cooled potatoes are among the richest everyday sources. Beans, lentils, chickpeas, oats, and green bananas are also excellent options.

How long should foods cool?

For the highest amount of resistant starch, refrigerate cooked foods for at least 8–12 hours.

Can I eat resistant starch every day?

Yes. Including naturally rich sources like beans, oats, lentils, potatoes, rice, and whole grains as part of a balanced diet is suitable for most people.