The refrigerated section at the grocery store is getting pretty crowded these days. First there were new alt-milks to compete with dairy milk and old standbys like soy and almond milk, then a variety of new alt-cheeses, meats, and yogurts popped up. And now, a new class of snacks—refrigerated protein bars—want to get in on the action.

That’s right—the OG of convenient, healthy snacks is getting in on the refrigeration game. It started with Perfect Snacks (which launched its OG Perfect Bar way back in 2005), but as they exploded onto grocery store shelves nation-wide, more and more brands started to jump on the refrigerated bar bandwagon. Think: CORE Bar ($48 for 16), OHI Bar ($32 for eight), Bright Foods Bars ($48 for six), and Phyter Plant-Based Food Bar ($55 for eight). Even OG protein bar brands like ProBars are getting into the refrigeration game.

This trend was even recognized by Whole Foods as being one of the top trends they’re seeing across customers for 2020, so we don’t see the movement dying down anytime soon. Yet, what is the point of moving these snacks to the refrigerated section? Here’s everything you need to know.

The healthy appeal of refrigerated protein bars and snacks

For starters, refrigerating bars and other snacks is to forego preservative use. “Refrigeration is often used to eliminate the need for preservatives in food products, and as such all of the refrigerated bars on the market I’ve found are preservative-free,” says Charlotte Martin, RDN.

Refrigerated bars are also refrigerated to maintain the integrity of their ingredients, which may soften at room temperature. “For example, many of these refrigerated bars, like Perfect Bars, are nut butter-based and as we all know nut butter isn’t very solid at room temperature,” says Martin. “Plus, refrigeration keeps the oils in nut butter from separating.”

These types of snacks often also have a high moisture content, which requires refrigeration to stay fresh. “For example, CORE Bars, the overnight oat bars, actually have ‘water’ listed as an ingredient, which makes sense since you need some liquid to make overnight oats,” says Martin. These bars need to be kept refrigerated to protect from spoilage and bacterial growth.

Looking for other healthy, minimally-processed snacks? Here’s how to find them with tips from a dietitian: 

In the case of Perfect Bar Original Peanut Butter ($3), the brand uses freshly-ground nut butter, whole food protein in the form of egg powder, rice protein, and dry milk, superfoods like powdered kale and papaya, and honey as the only natural binder, so refrigeration is required to maintain the bar’s consistency, texture, and freshness. Otherwise, it wouldn’t taste as good, says Leigh Keith, the co-founder and president of Perfect Snacks. “The cookie-dough-like texture is only able to be maintained with the freshness that comes from being in the fridge,” she adds.

Think of it like a jar of peanut butter, where the dry ingredients separate from the oil when left in the pantry. “Other dry bars, even when made with whole-food ingredients, typically contain less-fresh nut butter or more binding agents, so they are shelf stable for months and even years,” Keith says. Yet, by choosing a refrigerated bar as a snack, it might be able to stay fresh in the fridge for up to nine months and out of the fridge at room temperature for one week, she says.

Many refrigerated bars and snacks also offer probiotics (because ICYMI, gut health is very in right now). “Some refrigerated bars, like GoodBe and Cultured Snacking Co, have included probiotics in their formula to support gut and immune health,” says Martin. (Cultured Snacking Co also sells probiotic-infused nut butters.) However, this isn’t just a refrigerated thing, she says—just like you can buy a shelf-stable supplement, you can buy shelf-stable snacks fortified with probiotics. Case in point: Lola Probiotic Protein Bar and GoodBelly Probiotics Crunchy Bar.

Others have added popular buzzy ingredients—think collagen, matcha, and adaptogens—to appeal to a more wellness-minded consumer. Take Tyson’s new startup brand Pact Foods, which plans to launch refrigerated bites with collagen, prebiotic fiber, and kombucha.

Are they any better for you than regular protein bars?

Although most refrigerated protein bars and bites lack ingredients health-conscious consumers try to avoid, like preservatives and artificial sweeteners, it doesn’t mean they are inherently a superior choice to their shelf-stable counterparts.

“Although they may be preservative-free, that doesn’t mean they’re sugar-free, too,” Martin says. “Some refrigerated bars, just like some shelf-stable bars, can be packed with added sugar.” Translation: Yes, you still want to read the label to understand what’s in your bar of choice.

“As a dietitian, when it comes to choosing snack and protein bars, I focus less on refrigeration status and more on what’s on the nutrition label. I look to make sure there are adequate amounts of protein and fiber, and that the bar is low in added sugar,” Martin says. Make sure your bar has at least seven grams of protein and five grams of fiber to ensure it’ll keep you truly full between meals.

If a bar in the refrigerated section happens to meet these criteria, go for it! But don’t choose a refrigerated protein bar over a shelf-stable bar just because it’s refrigerated. They’re a cool choice (literally), but no need to lose your chill over them.

Craving other snack ideas? These are the picks that dietitians love. And the “rule of five” will help you find the best healthy snack every time.