Here is an excerpt from his account of his wartime service in World War I. I found his essay in a book, The Saturday Evening Post Book of the Sea and Ships which unfortunately appears to not be in print.
Tall and lanky as Rockwell was, he was initially was rejected for service as being underweight. He volunteered for civilian guard patrols for awhile and then tried to enlist again.
". . . The doctors at Pelham Bay Naval Enlistment Headquarters rejected me because I was 17 pounds underweight for my height and age, so I caught a train to New York, to try again at an enlistment center at City Hall.
The yeoman who weighed me there had been a student at the Art Students League. "You've overdone the starving-artist bit," he said. "We'll have to talk to a doctor."
He led me into a dark little office and explained my problem to a doctor who was sitting with his feet up on a desk and smoking a cigar.
"How much under is he?" asked the doctor, looking thoughtfully at my nakedness.
"Seventeen pounds," said the yeoman.
"Won't do," said the doctor. "We can waive 10 pounds but not 17."
The yeoman glanced furtively around.
"How about the treatment?" he whispered.
"He don't look big enough," said the doctor.
"I want to get in," I said, shivering as chill drafts ran up and down my bare legs. "What's the treatment?"
"Bananas, doughnuts, and water," said the doctor.
"You eat seven pounds' worth, we waive the other ten pounds, and you're in." He pulled open a file drawer. It was filled with bananas and doughnuts. I eased onto an icy chair, my teeth chattering. The yeoman drew a pitcher of water at the washbasin in the corner. The doctor heaped bananas and doughnuts around it. "Go to it," he said.
I began to eat and drink. After a while I staggered to the scales - five pounds to go. So I ate some more and drank some more. The doctor's cigar went out. The yeoman watched me intently.
"I'm going to burst," I said. "I'd better quit."
But the doctor and the yeoman had now adopted my enlistment as a personal cause; it wasn't just one sailor more or less, it was their battle against the Kaiser and all his forces of darkness.
"Come on," said the doctor, peeling a banana, "four more doughnuts and bananas, and more water."
I stuffed. And stuffed. And stuffed. The yeoman weighed me again. "We've won!" he shouted. I could hardly walk; the seven pounds of doughnuts, bananas, and water sloshing about in my stomach threw me off balance. But I managed to struggle into my clothes and totter home."