Canadian anthropologist Vilhjalmur Stefansson spent much of his time exploring the Arctic. Instead of taking vast stores of food, he ate what the Inuit ate: fish, caribou, walrus, and other meat, with few fruits and vegetables of any kind. This was in the early 20th century, when nutrition experts pushed raw vegetables for health, and encouraged minimal meat eating. Stefansson wrote about the Inuit diet, and encountered skepticism from those who couldn't believe it. To show them, Stefansson and an explorer friend went on a meat-only diet in 1928 -for an entire year. They began the experiment in a hospital where doctors could monitor their health, but that didn't last long.
While doctors condemned the diet as dangerous, Stefansson was defiant, attributing his increased vigor and “ambition” to his all-meat diet. Newspapers and magazines across the country ran stories on his experiment, contrasting it with the vegetable-heavy diets most doctors recommended. Soon, Stefansson left the hospital, having lost a few pounds, and continued his meat-eating endeavor from his New York apartment. Doctors examining the two men during the year-long trial reported that neither had heightened blood pressure or kidney trouble, the expected result of a carnivorous diet. The one thing lacking in their diet, Stefansson noted, was enough calcium.
Another conclusion Stefansson came to was that the protein he was eating wasn’t as important as the fat. He briefly flirted with “rabbit starvation,” a condition named for the fact that eating solely meat without sufficient fat can prove deadly. The human liver can only process so much protein sans fat without kickstarting the symptoms of protein poisoning: nausea, wasting, and death. Fat, and lots of it, is essential to the all-meat diet. Aquatic mammals are especially rich with fat, though. Recent studies point to genetics also playing a role in the Inuit aptitude for fatty, meat-filled diets, but as in Stefansson’s time as well as today, there remain questions about the relative healthiness of fats.
Read about Vilhjalmur Stefansson and his all-meat diet at Atlas Obscura.