 Bircher-Benner eventually adopted a vegetarian diet, but took that further and decided that raw food was what humans were really meant to eat.He was influenced by Charles Darwin's ideas that humans were just another kind of animal, noting that other animals do not cook their food.In 1904 Bircher-Benner opened a sanatorium in the mountains outside of Zurich called "Lebendinge Kraft" or "Vital Force," a technical term in the Lebensreform movement that referred especially to sunlight; he and others believed that this energy was more "concentrated" in plants than in meat, and was diminished by cooking.