Carbs have gotten a pretty bad rap over the past few decades, with "healthy" recipes and health-focused folks doing everything they can to avoid them altogether. But carbs actually aren’t evil, and there’s new focus on a specific type of carbohydrate that’s actually really good for you. New studies even say it may help manage type 2 diabetes and lower your risk of developing cancer.
Meet resistant starches. These carbs have caught fire on social media, with people posting a ton of videos of themselves refrigerating their rice and pasta in an effort to load up on this nutrient.
Of course, resistant starches aren’t covered in your standard health classes so it’s more understandable to have questions about what these are and why you should care about them. Here’s everything to know about resistant starches, plus how to reap all their healthy benefits.
Meet the experts: Alissa Lupu, CDN, is a nutritionist at NewYork-Presbyterian/Columbia University Irving Medical Center; Jessica Cording, RD, is the author of The Little Book of Game-Changers; Lindsay Malone, MS, RDN, is an instructor in the Department of Nutrition at Case Western Reserve University School of Medicine; Wael Harb, MD, is a board certified hematologist and medical oncologist at MemorialCare Cancer Institute at Orange Coast and Saddleback Medical Centers in Orange County, CA; Tiago Biachi, MD, PhD, is a medical oncologist in the Gastrointestinal Oncology Department at Moffitt Cancer Center
What is a resistant starch?
Starches are a complex carbohydrate that are found in plant foods, says Alissa Lupu, CDN, a nutritionist at NewYork-Presbyterian/Columbia University Irving Medical Center. Starch is digested, broken down into glucose (a.k.a sugar), and absorbed by the body.
Resistant starches, on the other hand, are a form of complex carbohydrate that the body cannot break down be digested. As such, they pass through to the colon and support the beneficial bacteria that live there, Lupu says.
Where do resistant starches come from?
All those TikTok posts about putting rice and pasta into the fridge? They're on to something, says Jessica Cording, RD, author of The Little Book of Game-Changers. “When you cool starchy foods, some of the starches that are digestible convert to resistant starches in a progress called retrogradation,” she says.
That doesn’t mean you need to eat cold pasta from now on. “The cooling process creates resistant starches that remain even when you reheat the food before eating,” Lupu says. “This is particularly true if you cool the foods in the refrigerator.”
Whole grains, beans, and seeds like flax and pumpkin inherently have resistant starch, Cording says. Bananas that are just beginning to get ripe (i.e. right past being green) also have some resistant starch, she adds.
While resistant starches are a healthier form of carbs, Cording says they’re not a magical nutrient. “Resistant starch won’t magically transform your body, but it is functional and helpful,” she says.
Why are resistant starches good for you?
Resistant starches actually act more like fiber than a traditional starch, according to Lindsay Malone, RDN, MS, an instructor in the Department of Nutrition at Case Western Reserve University School of Medicine. Of course, fiber has proven perks—it helps promote good digestive health, lowers the risk of heart disease and diabetes, and can help with weight management, per the Mayo Clinic. Resistant starch has some of the same benefits, says Cording*.*
Plus, resistant starch provides fewer digestible calories and serves as a prebiotic, feeding beneficial gut bacteria, per Malone.
When bacteria in the gut consume resistant starch, they produce gasses along with short-chain fatty acids, Lupu explains. “These short-chain fatty acids—butyrate in particular— provide nourishment to the cells of the colon and generally act to protect them,” she says.
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They can help with weight management.
If you've heard of this nutrient, it's likely in the context of it's weight management benefits. “When people ask me about resistant starch, they usually want to know if it’s going to help them lose weight, regulate their blood sugar, and if it’s the same as Ozempic,” Cording says. Spoiler: It's not.
But resistant starch can help you feel full after a meal, and that may lower the risk you’ll overeat, Cording says. Resistant starches are also proven to help support weight loss and regulate your metabolism, per a 2020 study published in the International Journal of Molecular Sciences.
What other new health benefits have been discovered?
It's not just the weight loss benefits that make this carb especially exciting to nutritionists and doctors. Resistant starches can help reduce blood glucose spikes after meals, which would make them useful in treating diabetes, Lupu says.
In fact, a 2024 scientific article published in Nature Metabolism linked resistant starch to better insulin sensitivity, and a 2023 Frontiers in Nutrition scientific review found it can improve blood sugar control.
Another 2024 review published in the Journal of Diabetes Investigation found that resistant starches actually help your body use blood sugar efficiently, and lower glucose levels after eating, which is great for people with type 2 diabetes. (The effect is similar to following a low‐glycemic index diet.)
And that's not all. These starches also show promise in helping prevent cancer. Scientists know that resistant starch can promote a more diverse gut microbiome, which boosts gut health and helps prevent colon cancer. But a 2022 study published in Cancer Prevention Research found that taking resistant starch supplements for four years lowered the risk of cancer by more than 60 percent in people with Lynch Syndrome, a genetic condition that raises the risk of developing several types of cancer.
The researchers also discovered that those who took resistant starch supplements seemed to experience protective effects against cancer at least 10 years after they stopped taking the supplements. (The supplement dose of 30 grams is similar to what you'd get with eating one unripe banana a day.)
The exact reason for this anti-cancer effect isn't clear, but experts have some theories. "Resistant starch may influence cancer risk beyond the colon by improving overall gut environment, reducing inflammation, and supporting immune surveillance," says Wael Harb, MD, board certified hematologist and medical oncologist at MemorialCare Cancer Institute at Orange Coast and Saddleback Medical Centers in Orange County, CA. They may also support genomic stability (i.e. preventing gene mutations), lowering the odds of developing certain cancers over time, he adds.
"More studies are needed, but these findings suggest that modulating the gut microbiome can impact the risk of other tumors in Lynch syndrome, not only colon cancer," says Tiago Biachi, MD, PhD, a medical oncologist in the Gastrointestinal Oncology Department at Moffitt Cancer Center.
While research into the health perks of resistant starch is ongoing, the data is promising so far. So, a little leftover pasta is may not be a bad choice for dinner.
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Korin Miller is a freelance writer specializing in general wellness, sexual health and relationships, and lifestyle trends, with work appearing in Men’s Health, Women’s Health, Self, Glamour, and more. She has a master’s degree from American University, lives by the beach, and hopes to own a teacup pig and taco truck one day.