Query: What is the European equivalent of "Qi"?
Context: According to Walter Gratzer, the study of nutrition probably began during the 6th century BC. In China, the concept of Qi developed, a spirit or "wind" similar to what Western Europeans later called pneuma. Food was classified into "hot" (for example, meats, blood, ginger, and hot spices) and "cold" (green vegetables) in China, India, Malaya, and Persia.