U.S. astronaut Leroy Chiao and Russian cosmonaut Salizhan Sharipov cut back on meat, potatoes and vegetables by half and made up for the lost calories with sweets.
"Both of us ended up losing a few pounds, but I guess that's nothing we can really complain about," Chiao said during a news conference from space. "A lot of people would be happy to lose about five or 10 pounds."
The need for rationing ended a few days ago after a Russian cargo ship arrived last weekend with 440 pounds of food for Chiao and Sharipov. Also packed into the cargo ship were Christmas cards and photographs.
If the Russian ship had failed at liftoff or had been unable to dock, the space station would have had only enough food to last seven to 14 days, and the crewmen would have had to abandon the orbiting outpost and return to Earth, according to NASA.
"That's something that neither of us, nobody really, wanted to have happen," Chiao said. "All throughout this whole thing, we kept real good spirits. Salizhan and I have been keeping each other up, joking around and it's been very pleasant even with some of the shortages."
One reason for the food shortage was that ever since the shuttle fleet was grounded by the Columbia disaster, NASA has relied on Russian cargo ships to deliver supplies to the space station. And the Russian ships cannot carry as much as the shuttle.
Chiao also blamed the shortage on the previous crew members, who had permission to take some of the current crew's supply because they were lacking food variety.
"The last crew had gotten into our food and had failed to actively report to the ground what they had taken out of our allotment," Chiao said.
The food supply had never gotten so low before, and no mandatory dieting had ever been implemented before during the four years that the space station has been occupied permanently.
The crew members were forced to reduce their daily intake of 3,000 calories by 5 percent to 10 percent.
"There were lots of desserts and candies on board that we could kind of snack on during the day," Chiao said. "It was not an unhealthy diet, but not an ideal diet."
Chiao and Sharipov are 2 1/2 months into a six-month stay in space.
"I think it will be great to make the new year in space," Sharipov said in broken English. "We hope that next year is one of the happiest years for all."
NASA hopes to resume shuttle flights as early as May.
By Mike Schneider