1. Meals have to pass the "Vomit Comet" test
NASA has a whole staff of dietitians, engineers, and scientists who create astrofood at the Food Systems Engineering Facility in Houston. And one of their duties is taking every new food item on the NASA zero-gravity KC-135 airplane (aka "Vomit Comet") to see how it'll react in microgravity. If it passes this and several more tests, it's approved for flight. Also, here's a bunch of amateurs in the Vomit Comet, in case you were curious.
2. You can bring your own food
NASA makes sure its spacemen and ladies have all the food they need, but it also lets them pack their own stuff to break up the monotony of the menu, which operates on a cycle. "Whatever you want to bring has to be cleared by the food lab. No glass containers, nothing that’s really crummy, is allowed to go up," Marshburn says. "And I’m sure they have other restrictions I don’t know about. But we were allowed for a five-month stay about nine containers." Choose your snacks wisely.