During his 70-day, record-setting expedition skiing across Antarctica, Ryan Waters burned 7,000 calories a day, fixed a broken tooth and never fought with his partner.

Waters, of Boulder, and his partner Cecilie Skog, of Norway, completed the first unsupported, unassisted -- no food stashes, no wind-assisted kite skiing -- crossing of Antarctica on Jan. 21.

Back in Boulder on Tuesday, Waters, 36, sported shaggy hair (soon to be cut) and the steady, unflappable countenance one might expect of a person who had followed a rigid schedule across 1,100 miles under the midnight sun to do something no one had done before.

"The physical stuff, you can either do it or you can't," Waters said. "We felt very good, we felt strong, we knew we could do it physically. But the part we didn't know was, there are so many things that go wrong that could end the trip."

But in 70 days, the pair never experienced a trip-ending broken ski, tent or bone -- just a few minor difficulties.

"The skins of our skis, we ended up screwing them on, because they kept coming off," he said. "She broke a tooth, so I was in there with the dental kit repairing a filling."

When things went wrong, Waters said he drew from his years of experience as a high-altitude mountaineer and climbing guide to fix them.

"You have to have screws, glues, you have to have a hand drill," he said. "And everything you bring, you have to think through, 'What if this breaks?'"

With so much equipment and food to carry, Waters and Skog started the trip pulling 300-pound sleds. Waters purposely gained about 25 pounds in the last month before leaving, knowing he would waste away at the effort; he finished the trip about 30 pounds lighter.

"Cecilie was the same way," he said. "She was like a skeleton at the end."

Skiing six to nine hours a day in the cold burns 7,000 calories a day, he said. But even scarfing chocolate and cookies from a "snack bag" while skiing doesn't compensate for that many calories. So they went on 5,000 calories a day.

"It doesn't matter that it's the same foods you've been eating," he said. "You can't wait to eat dinner."

The pair arrived at the South Pole on New Year's Eve -- on schedule. People working at the National Science Foundation station there offered them treats, but because the trip was unsupported, they turned them down.

"We couldn't accept anything," Waters said. "People there were like, 'Hey guys, have some coffee, have a piece of cake.' But we said, 'Sorry, we can't take anything -- soap, nothing.' Because we wanted to be really pure about no support."

Waters said that he and Skog never had an argument on the expedition. The explorers Skog knew back home -- Norway has a long tradition of polar exploration, he added -- had advised them to always stay positive, that negativity would wear them down.

"By the last week, your nerves are so frayed, you've been out there so long -- you get a little short with each other, saying, 'Hand me that!'" he said. "But we'd always be like, 'I'm sorry for saying that.'"