Nutrition Science and Everyday Application - beta v 0.1

Introduction to Energy Balance
On December 26, 2018, 33-year-old Colin O’Brady of Portland, Oregon, became the first
person to cross the landmass of Antarctica solo, unassisted, and without any resupply
shipments. Others had crossed the continent with the help of a wind sail to propel them over
the ice or with resupply drops along the way—both ways of saving precious energy—but
O’Brady completed the 926-mile trek only on skis, pulling a sled packed with food, fuel, and
supplies the entire way. Speed was important, because he was racing another man, Louis
Rudd, a 49-year-old British Army captain. And of course, he didn’t want to run out of food
hundreds of miles from the finish. Rudd finished the Antarctica crossing just two days after
O’Brady.
Figure 7.1. Endurance athlete Colin O’Brady, photographed in March 2016
To prepare for the expedition, O’Brady and his team had to make careful calculations
to estimate his nutrient and caloric needs. He’d be skiing all day, every day for about two
months, in below zero temperatures and against constant wind. O’Brady estimated that he’d
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