What actually happened was that 28 men spent nine months frozen in the Weddell Sea pack ice, followed by five months camped on the ice after the ship was abandoned, followed by seven days in open boats, followed by a week on Elephant Island before the James Caird departed, followed by four months more on Elephant Island for 22 of the men. The food supply was not designed for this.
Green’s management of the supplies began with what was available from the ship and continued with what could be obtained from the environment. Seals were the primary supplement — their meat provided protein and their blubber provided fuel for the stoves. Penguins provided both. On Elephant Island, the availability of elephant seals and penguins at a rookery was what made survival possible; without the wildlife of the island, the caloric arithmetic would not have worked.
But the availability of raw seal meat did not automatically produce adequate nutrition. Green cooked it. He improvised stoves and fuels — the seal blubber was burned in improvised lamps and stoves, supplemented by whatever other combustibles were available. He maintained something like meals — not the meals the men had signed on for, but structured eating events that provided caloric intake and the psychological comfort of food consumed together rather than individually, from the raw materials.
The cook’s role in an emergency of this kind is invisible in proportion to its success. When the food is adequate, when the eating is organized, when the men are sustained, no one remarks on it. The diaries note Shackleton’s decisions and Worsley’s navigation and McNish’s carpentry because those efforts were dramatic and visible. Green’s continuous, daily provision of food to 28 men through 22 months of extraordinary conditions is documented mainly in the margins — a note here about rations, a reference there to a meal — precisely because it worked well enough not to fail dramatically.