ABSTRACT
Singh (1977) noted that diet terminology is often used very imprecisely and ambiguously, such as diets “containing starch, casein or wheat germ described as ‘chemically defined.’” Singh continued, “To some authors, a ‘synthetic’ diet is a mixture of nutritive substances, with perhaps a plant preparation with yeast, or vitamins or sugar added; to others it is a mixture of pure chemicals only.” Dougherty (1959) provided a concise and logical set of definitions that have been used by many authors to give consistent meanings to diet formulation terminology. Dougherty described holidic diets as ones whose components are completely known and oligidic diets as ones whose components are not fully or not even nearly well characterized. Meridic diets fall between, with some components well characterized (or defined) and others poorly defined. Meridic diets can be considered intermediary between holidic diets and oligidic diets (Dougherty, 1959).
