Remember in the classic Star Trek series how you would insert some colored disks into a food dispenser slot and out would come chicken noodle soup or whatever else? Or in Star Trek: The Next Generation, Picard would just ask for "tea, Earl Grey, hot," and it would materialize?
It turns out that in real life, food preparation for astronauts is much more difficult. The International Space Station doesn't even have a refrigerator! This article from Space.com is chock full of the issues about food preparation for long-term space missions, such as going to Mars.