Vilhjalmur Stefansson was an arctic explorer who lived with Eskimos for several years in 1904 and 1905, studying them. He adopted their all-meat diet and returned to New York, promoting this diet as healthful. Doctors there doubted humans could really survive on an all-meat diet, so Stefansson and a colleague subjected themselves to a clinical trial under medical supervision. First, the doctors insisted on giving them a high-protein version of an all-meat diet, and both men rapidly fell sick. These are the high-fat macros they switched to after a short while, which rapidly reversed all the negative effects of the high-protein diet.