7 Foods That Are Healthier Chilled, According to Science

Good news for those who meal-prep: Not only is it time-saving, it might be healthier than you think. As it turns out, chilling certain foods before eating them amps up their benefits.

When rice, pasta, potatoes, or oats cool, their starch changes into something called “resistant starch”—a fermentable fiber that has been linked in numerous studies to more stable blood sugar, longer satiety, and happier intestinal flora.

For those who love a bit of nerdy nutritional info, here’s a little more about resistant starch: Unlike other carbohydrates that break down into sugar, it passes through to the colon, where it eventually produces short-chain fatty acids called butyrate, which is considered the ultimate for a healthy intestinal barrier. Because this starch “resists” being digested in the small intestine and ferments in the large intestine, it also acts as a prebiotic that feeds beneficial gut bacteria.

But the healthy cool-down effect also extends beyond our favorite carbs: studies show that polyphenols and antioxidants in some vegetables are better preserved or even enhanced when they are first heated and then cooled again.

Seven foods that are healthier cooled

Several studies show that rice that has been cooked and cooled completely in the fridge contains significantly more resistant starch than freshly-cooked rice. After just twelve hours in the fridge, the proportion can increase many times over and has been shown to significantly lower increases in blood sugar.

Pasta also undergoes the same starch shift when chilled. A nutritional study showed that after 24 hours of cooling and subsequent gentle reheating, cooked pasta has significantly slower starch digestibility than freshly prepared pasta. This less rapidly available starch may also lead to a milder rise in blood sugar after eating.

Oats are already very healthy. The grain is rich in beta-glucans, which clinical studies have repeatedly linked to better blood sugar regulation, cholesterol reduction, and a more stable microbiome.

But when oats are cooked and then cooled completely, the starch composition also changes. Several experimental studies have shown that type 3 resistant starch is formed during cooling, producing the beneficial short-chain fatty acids known as butyrate. To get the benefits, swap your hot morning oatmeal for overnight oats.

Potatoes have some of the most significant resistant starch benefits. In a study by the University of Surrey, it was shown that fully cooled potatoes can reduce blood sugar rise immediately after eating (also called postprandial blood sugar rise) by up to 40 percent.

That said, you don’t have to be eat your tots completely cold: When carefully reheated—say, a quick 90 seconds in the microwave—much of the benefits remain. Try making your potato salad, jacket potatoes, or mash from potatoes that were cooked the day before and reheating them: They’ll be healthier than the freshly-cooked version, which might just burn your tongue anyway.

Blanched green vegetables such as beans, broccoli, and sugar snap peas also benefit from the effect of cooling—albeit for different reasons. A study documented that rapid-cooling green vegetables in an ice water bath after blanching significantly reduces the loss of polyphenols and vitamin C up to 25 percent. Unfortunately, that doesn’t mean frozen vegetables are necessarily healthier: Unblanched, frozen vegetables lose significant antioxidant activity and ascorbic acid in comparison.

Studies show that heating tomatoes releases more lycopene, the powerful antioxidant associated with cell protection and anti-inflammatory effects.

But health benefits are further enhanced when the tomatoes are cooled down again. Here is an example: When tomato sauce made from fresh tomatoes cools slowly, some of this lycopene changes structure into a form that is easier to absorb. In technical terms, this is called “isomerization.” In simple terms, it means the beneficial lycopene becomes easier for the body to use.

Last but not least, barley also benefits from this cook-and-cool process. This is because barley, like oats and potatoes, forms resistant starch when it is cooked and cooled. Studies link this to improved blood sugar regulation, longer satiety and the promotion of butyrate-forming intestinal bacteria. In addition, barley provides beta-glucans, which have shown positive effects on lipid profiles and inflammatory markers in clinical studies.

If you don t know the best way to eat barley, here s a suggestion: Cook it like rice and enjoy it chilled as the base in a colorful bowl with citrus dressing, roasted and fresh vegetables, fresh herbs, and a protein source of your choice.

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