Opson and sitos were Classical Greek food groups, mainly used for moral education, to teach
sophrosyne.
Mitahara, a concept of moderate diet found in early-first-millennium
Sanskrit texts, categorizes food into groups and recommends eating a variety of healthy foods, while avoiding the unhealthy ones; it also considers foods to have emotional and moral effects. Indian foodways had a substantial influence on European organisations such as the
Vegetarian Society, which cited Indian diets as proof that a healthy vegetarian diet was possible, and were actively involved in public debate on nutrition. In the 20th century, food groups became widely used in public health education, as a tool to reduce nutritional deficiencies. As early as the 1980s, researchers were criticizing food groups, saying that they were a concept useful for teaching people to avoid
nutritional deficiencies, but that nutritional deficiencies were no longer major causes of diet-related disease in affluent societies. Since these are caused by unhealthy food, not by diets lacking of a specific nutrient, they thought that food groups would have to be entirely discarded, or entirely revamped to make them useful in nutritional education in
post-industrial countries.
United States The
USDA promoted eight basic food groups prior to 1943, then seven basic food groups until 1956, then four food groups. A food pyramid was introduced in 1992, then MyPyramid in 2005, followed by MyPlate in 2011. Dietary guidelines were introduced in 2015 and slated to be rereleased every five years. The 2020 guidelines were to be released in spring 2020. Recommended Dietary Allowance recommends daily servings of each group for a
healthy diet. In the United States for instance, the
USDA has described food as being in from 4 to 11 different groups. ==The most common food groups==