answer:You can’t be, “On a diet,” unless you know what you’re eating. Diet: a : food and drink regularly provided or consumed b : habitual nourishment c : the kind and amount of food prescribed for a person or animal for a special reason Middle English diete, from Anglo-French, from Latin diaeta, from Greek diaita, literally, manner of living, from diaitasthai to lead one’s life. Everyone in the world who eats food, is always “on a diet.”