Resistant Starch: The Reason Rice, Pasta, Other Carbs Might Be Healthier As Leftovers

Fact checked by Nick Blackmer

• Resistant starch is naturally occurring in foods like whole grains, legumes, and some seeds.

• TikTok influencers claim that consuming resistant starch could have certain health benefits like gut health, balanced blood sugar, and potential weight loss.

• Experts noted that the trend is simple and low-risk, but it also might not yield health benefits for everyone who tries it.

Should you refrigerate your rice before eating it?

TikTok’s most recent culinary trend involves increasing the resistant starch in certain foods by storing them in the refrigerator before you eat them.

The idea is that when you allow high-carb foods like cooked potatoes, rice, or pasta to sit in the refrigerator (or freezer) for hours, or even days, it gives them a chance to develop more resistant starch.

Resistant starch gets its name from the way it resists digestion in the body.

Unlike other carbohydrates, resistant starch is not susceptible to the action of amylase, an enzyme in the small intestine that breaks food down into smaller parts. Because of this, it arrives intact in the large intestine.

Once there, resistant starch can only be broken down by specific healthy gut bacteria.

“Resistant starch is naturally found in whole grains, legumes, and some seeds,” Kim Kulp, RDN, gut health expert and owner of Gut Health Connection in the San Francisco Bay Area, told Health.

According to TikTok influencers, consuming more of this unique starch (which functions like fiber) could have health benefits like stabilizing blood sugar, boosting the gut microbiome, and promoting weight loss.

“These microbes then produce short-chain fatty acids, including butyrate, which has been shown to protect the lining of the intestines, and may improve insulin sensitivity, influence appetite hormones, and reduce abdominal fat,” Kulp said.

Proponents claim that simple food storage techniques are an almost zero-effort way to achieve these effects.

“What is interesting is that you will not even have to change what you typically eat in order to add more resistant starch to your diet, as this method is all about how you prepare and consume common foods,” Laura Purdy, MD, board-certified family medicine physician, told Health.

People are taking notice of this trend and trying it for themselves—#resistant starch currently has over 1.7 million views on TikTok.

Here’s what you need to know about how food storage techniques may impact your nutrition, as well as whether or not it’s worth trying to optimize resistant starch in your diet.

Increasing Resistant Starch

To increase the resistant starch in cooked potatoes, pasta, beans, or rice, say influencers, all you have to do is place them in the refrigerator for one day. As they sit undisturbed in low temperatures, they change on a molecular level, creating more starch that resists digestion and ultimately can promote health.

Related: Eating More Whole Grains, Non-Starchy Veggies Can Help Prevent Midlife Weight Gain

Does Resistant Starch Really Create Health Benefits?

To assess whether TikTok’s health claims around resistant starch are true, it’s helpful to examine them one by one.

But first, the all-important question: do these storage methods even do what they say?

According to Kulp, this is one time a TikTok trend holds up to scientific scrutiny.

“Cooking and cooling foods like pasta, potatoes, and rice, and freezing bread, can increase the content of resistant starch in these foods,” she said.

Purdy agreed. “Some starches may lose their original composure due to heating or cooking, and if they are later cooled, a new structure is created,” she said. “This new structure may be resistant to digestion and can lead to additional health benefits.”

As for individual health claims around high-resistant starch foods, the evidence is somewhat less cut and dried.

Among the most promising, though, is the claim that refrigerated foods like cooked rice or pasta could help maintain steady blood sugar. Kulp pointed to a 2023 study that showed that freezing bread slowed the rise in blood sugar, possibly decreasing the risk of weight gain and type 2 diabetes.

But, other research doesn’t support the idea of resistant starch leading to weight loss.

A 2014 review concluded that, though resistant starch could increase fat oxidation and reduce fat storage, no direct data has shown that it has any impact on body weight, calorie intake, or energy expenditure.

And what about gut health?

It’s true that the fermentation of resistant starch in the large intestine creates short-chain fatty acids (SCFAs) like butyrate. Research shows that this particular SCFA can reduce inflammation in the intestines and modulate intestinal motility (in other words, get your gut moving).

But Kulp explained that not every person will have the same gut-level response to resistant starch.

“Only two species of gut microbes, Ruminococcus bromii and Bifidobacterium adolescentis, are able to turn resistant starch into the health-promoting compound butyrate,” she said. “Since different people have different microbiomes, not everyone will benefit from resistant starch.”

In the end, refrigerating or freezing your favorite carbohydrates probably won’t do any harm—and it could lead to some modest health benefits.

According to Purdy, since this trend is simple and low-risk, it may be worth a try. “If this method is interesting to you and works for you, then why not?”

Related: What Are Complex Carbohydrates? — And 28 to Add to Your Diet

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