That has always been the main problem.
Water can be recycled, and is, but food is a different matter, along with the long term health effects of space travel...............
At first when the guy was telling me all this stuff I thought he might have been full of crap. Then he gave me his business card.
I looked him up and became friends with him on Linkden. I still am today. Except he is now retired from NASA.
He had been a pilot during Vietnam. He said one of the things he was most proud of was his simulator landings of the Space Shuttle. IF he had gotten the chance to go into space he would have been the pilot of the shuttle. He also would have been the first African American to go into space. But they chose the other guy.
There has already been a documentary on this.