In 1971, a 27-year-old, 456-pound man went to the University of Dundee’s department of medicine in Scotland looking for help. Patient A.B., as doctors referred to him, needed to lose weight. His physicians recommended a short but drastic course of action: stop eating altogether. The patient responded so well to a brief stint without food that he decided to prolong the deprivation—for more than a year.
“[H]is fast was continued into what is presently the longest recorded fast (Guinness Book of Records, 1971),” the clinicians wrote in a 1973 case report, claiming A.B. suffered little or no untoward effects on his health.1 And at the end of his 382-day dietary abstinence, during which he had ingested only vitamin supplements, yeast, and noncaloric fluids, A.B. had lost a remarkable 276 pounds. When doctors checked back in on A.B. five years later, their patient reported gaining back only about 15 pounds.
Although ...
