What do astronauts do when they need a sugar fix? Reach for the candy bag—or, as they’re labeled aboard the International Space Station (ISS), “candy coated chocolates.”

Chocolate candy and other desserts have been staples of the astronaut experience since the Apollo program. Apollo 11 astronauts took dehydrated chocolate pudding to the Moon in plastic bags, and Neil Armstrong was fond of the bite-sized, gelatin-coated fruit cake.

At the beginning of the space program, food options were fairly regimented. Breakfast, lunch, and dinner for each day of the mission came pre-packaged, leaving astronauts with little flexibility. Now, during preparation for a stay on the ISS, astronauts get to pick and choose from a variety of foods including desserts and candy. These are often the same options that we find in grocery stores on Earth, though NASA, as a government agency, doesn’t use brand names—so, M&Ms® become “candy coated chocolates.”

M&Ms® are the candy of choice aboard the ISS for many reasons, both practical and personal. They are a perfect fit for the conditions aboard the space station because they’re bite-sized and self-contained. That means that astronauts won’t run the risk of losing stray crumbs while they snack.

“When you’re talking about a chocolate bar that you have to bite or break, a piece could fly off,” space history curator Jennifer Levasseur said. If crumbs get lost, the pieces could get wedged behind the maze of cables, computers, cameras, and equipment that keep the station running. “Anything you can eat in daily life that could leave crumbs behind is potentially bad news for the spacecraft.”

M&Ms® solve that problem, and are large and colorful enough that if a piece gets away, the astronauts have an easier time tracking it down. The same things that make them practical for eating aboard the ISS also make them a useful demonstration tool. Astronauts often use M&Ms® as projectiles for demonstrating microgravity—what we might commonly think of as weightlessness—and suspending them inside what Levasseur describes as “globs” of water.

Scientific usefulness aside, there’s the sweet taste. Since the way blood flows through the body is different in space, stronger flavors are preferred. Instead of Earth’s gravity pulling the body fluids down as your heart pumps, blood flows evenly through the torso and head while floating in space. Astronauts report feeling congested, similar to a head cold, which makes their food taste bland. So, stronger tasting foods, like chocolate or spices, are more enjoyable the astronauts.

There’s also a human connection at the heart of these space snacks. Food is a central way that astronauts maintain a connection to home—whether it’s enjoying a cup of coffee in the morning, or having traditional foods from their respective cultures aboard the ISS. That taste of home brings a comfort and normalcy to their time in space.

“Chocolate is a universal thing and has psychological effects here on Earth,” Levasseur said. “It serves the same purpose as a comfort food in space.”