NASA's first job, before it put a man in space, was to find the meal that leaves the least behind. The answer was steak and eggs, and it has been the launch breakfast for 65 years.
The problem was the suit. A Mercury astronaut was sealed into a pressure suit, bolted into a capsule the size of a phone box, and left on top of a rocket for hours. He could not take anything off. There was no toilet, and no plan for one.
So in July 1960 the Air Force handed the question to a nutritionist called Beatrice Finkelstein. She had to feed the man so he stayed strong, clear-headed and full, for as long as it took, on the least possible waste.
She wrote a menu for the last 3 to 4 days before flight. High protein, low residue. Meat, eggs, very little else. Residue is the polite word for whatever the body cannot use and has to send back out. On her figures, beef and eggs produced almost none. The body took nearly all of it.
On the morning of 5 May 1961, Alan Shepard sat down to steak and eggs, went out to the pad, and became the first American in space.
It worked so well that nobody dared change it. John Glenn ate it. The crew of Apollo 11 ate it on the morning they left for the Moon. Shuttle crews ate it. Astronauts are superstitious, and this is the one ritual with a medical file behind it.
Look at what that file says. The best funded engineers on earth needed a food that was nearly all nutrition and next to no waste, to fuel a man through the most demanding day of his life, and they did not pick porridge.
Down here the same breakfast comes with a warning, and we are advised to swap it for the bran.
NASA ran the test in 1960. The bran is the residue.