This tidbit was among more than 700 pages of once-secret material linked to the life and times of the world's first spaceman that were released by Russia ahead of the April 12 anniversary.
The historic space shot turned Gagarin into an instant celebrity whose boyish charms became a powerful propaganda weapon for the Soviet Union as it scrambled to win its ideological battle against the United States during the Cold War.
His boy-next-door grin and outsized helmet became a staple of Soviet stamps while his heroism turned into a subject of elementary school literature that became comparable to the teachings of Lenin.
Russian authorities -- with their own space programme in trouble -- have grabbed on to that glory by making the Gagarin celebrations into a national event stretching from the halls of the Kremlin to the International Space Station.
Russian President Dmitry Medvedev is planning a visit to the mission control centre outside Moscow while his mentor and predecessor Vladimir Putin will hold his own meeting with Russian and Ukrainian cosmonauts in Ukraine.
But making the biggest news among Russians this weekend were files revealing the conversation Gagarin had while strapped into his capsule with chief rocket designer Sergei Korolyov -- a man who became a legend in his own right.
Gagarin is best remembered by a generation of Russian for pronouncing "Poyekhali!" as his Vostok spacecraft lifted off the ground.
The phrase can be translated as either "Let's Go!" or "We're Off!" and is now a regular part of the Russian lexicon.
But the Russian Internet was abuzz with what Gagarin said moments before his famous catchphrase.
One of Korolyov's biggest worries appeared to be that the would-be hero had enough to eat once he touched down on Earth.
"There in the flap you have dinner, supper and breakfast," the father of the Soviet rocket programme told Gagarin by radio as the clock ticked down.
"You've got sausage, candy and jam to go with the tea," Korolyov went on. "Sixty-three pieces -- you'll get fat! When you get back today, eat everything right away."
Gagarin joked back: "The main thing is that there is sausage -- to go with the moonshine."
Korolyov appeared to take the joke in stride.
"Damn. This thing is recording everything, the bastard," the scientist said in reference to the relay recorders.
The website also published a photograph of the original faded sheet on which the conversation is transcribed.
Lifenews.ru added that Gagarin appeared to be singing and whistling to himself while mission control continued conducting various last-minute checks.
Not all of them went smoothly.
Gagarin at one point is told to rip off some adhesive tape and adjust a piece of equipment because "we forgot to tape that thing".
He is later told that access hatch would have to be readjusted because "one of the contacts failed to light up" on the mission control panel.
Gagarin appeared to take everything in stride and began happily reporting all he saw once his spacecraft was finally aloft.
Various historians noted that one of the Soviet officials' biggest fears was that their cosmonaut would lose consciousness once he became weightless.
"The sensation of weightlessness feels nice," Gagarin reported to ground control at one point. "Everything is swimming."