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.

“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.

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.

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.

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?”