In 1971, a 27-year-old, 456-pound man went to his local university department of medicine to get advice on how to lose weight. Their response was startling but simple: stop eating altogether. While most people would look aghast and think the doctors were nuts, this guy was desperate enough to give it a try. His results over the ensuing weeks were so dramatic that he decided to prolong the fasting deprivation—for more than a year! He ate nothing but vitamins, non-caloric fluids, and yeast for a whopping 382 days. He lost 276 pounds and gained himself a spot in the Guinness Book of World Records. What’s more, he did so with no ill health effects. When the doctors checked back in on him five years later, he had gained back only about 15 pounds.