In November 1944, with famine looming across a war torn Europe and Asia and no one sure how to safely feed the starving, physiologist Ancel Keys, creator of the K ration, launched a study at the University of Minnesota’s Laboratory of Physiological Hygiene. From more than 400 applicants he picked 36 healthy young conscientious objectors from the Civilian Public Service, almost half from peace churches such as the Mennonites, Quakers and Church of the Brethren. After 12 weeks on about 3,200 calories a day, they spent 24 weeks on roughly 1,560 calories of turnips, rutabagas, potatoes, dark bread and macaroni while working in the lab and walking 22 miles a week.

Keys plotted a curve for each man to lose 25 percent of his body weight and cut the rations of anyone whose loss stalled. Resting heart rates fell into the 30s, legs swelled with edema, and personality tests run by Josef Brozek showed spikes in depression, hysteria and hypochondriasis, while food became an obsession. The restricted refeeding phase proved even harder, and subject Sam Legg cut off three of his fingers with an axe without being able to say whether it was deliberate. Keys rushed refeeding guidance to relief workers and in 1950 published The Biology of Human Starvation, findings that later reshaped how eating disorders are treated.

• Two men dismissed from the study for scavenging food
• Volunteers collecting cookbooks and some changing career plans to become chefs
• Men who felt their intelligence fading scored no lower on standardized cognitive tests
• Why small extra rations during rehabilitation woke the hunger drive instead of easing it
• The finding that starvation itself produces the psychological profile once blamed on eating disorder patients