When it comes to fibre, most people think of things like bran, whole grains, and vegetables — and while those are all essential, there’s a lesser-known but incredibly powerful type of fibre worth paying attention to: resistant starch.
Unlike regular starch, resistant starch “resists” digestion in the small intestine. Instead of being broken down and absorbed like other carbohydrates, it travels to the large intestine, where it’s fermented by gut bacteria. This fermentation process produces short-chain fatty acids (SCFAs), most notably butyrate, which plays a key role in supporting a healthy gut environment.
What Are the Benefits of Resistant Starch?
Resistant starch acts as a prebiotic, meaning it feeds beneficial bacteria in your gut. In turn, these microbes produce compounds that help:
✅ Reduce inflammation in the gut and throughout the body
✅ Strengthen the gut lining, reducing the risk of “leaky gut”
✅ Improve insulin sensitivity and support blood sugar regulation
✅ Enhance satiety, which may help with appetite control
✅ Support regular bowel movements
One of the most studied benefits is the production of butyrate, a short-chain fatty acid shown to reduce colon inflammation, support immune health, and protect against colorectal cancer (Bindels et al., 2015).
Where Do You Get Resistant Starch?
Resistant starch occurs naturally in a variety of plant-based foods, but certain cooking and cooling processes can increase its levels. Here are some of the best sources and how much you need to eat to improve your intake of resistant starch:
🥔 1 cup cooked and cooled white potato = ~4g
🍚 1 cup cooked and cooled brown rice = ~3g
🍌 1 small green banana = ~4g
🥣 ½ cup cooked and cooled oats = ~2g
🥄 ½ cup cooked lentils or legumes = ~3g
Other sources include barley and cooked and cooled pasta.
Why cooled? Cooking starches like potatoes, rice and oats and then cooling them increases their resistant starch content through a process called retrogradation – the starch molecules restructure in a way that makes them harder to digest, increasing their prebiotic power.
How Much Do You Need?
Studies suggest 15–20 grams of resistant starch daily can support optimal gut health. (Topping & Clifton, 2001). However, most Australians fall short of this, with average intakes under 4 grams daily.
It’s best to increase slowly to avoid bloating or discomfort – your gut microbiome needs time to adapt. Start by including one serving of resistant starch-rich food per day and gradually build up.
Here’s a simple day that hits the mark:
- Breakfast: Overnight oats made with ½ cup oats + chia + banana (6g)
- Lunch: Lentil salad with ½ cup cooked lentils and brown rice (6g)
- Dinner: Roast veggie bowl with 1 cup cooled potato + leafy greens (4g)
Add your protein sources to the above of course!
Quick Tips to Boost Your Intake
- Make extra rice or potatoes at dinner, store in the fridge, and eat cold the next day or lightly reheated.
- Swap regular bananas for slightly green ones.
- Batch-cook lentils and add to soups, salads or wraps.
- Use overnight oats or soaked bircher as a swap for cooked porridge from time to time
Adding more resistant starch to your diet is a simple and effective way to support gut health, feed your microbiome, and promote long-term wellbeing. It’s a small change that can make a meaningful difference, and with so many easy, everyday food options, it’s more accessible than ever.
References:
Bindels, L. B., Delzenne, N. M., Cani, P. D., & Walter, J. (2015). Towards a more comprehensive concept for prebiotics. Nature Reviews Gastroenterology & Hepatology, 12(5), 303–310.
Topping, D. L., & Clifton, P. M. (2001). Short-chain fatty acids and human colonic function: roles of resistant starch and non-starch polysaccharides. Physiological Reviews, 81(3), 1031–1064.
