Diet/ˈdaɪət/ Definition 1 of 3Pro Tip 1/3Cultural Importance Different cultures have diets associated with specific foods. Mediterranean diets are high in olive oil and fish. Pro Tip 2/3Personal Choice 'Diet' can reflect personal choices, including ethical and health reasons. He switched to a vegetarian diet for ethical reasons. Pro Tip 3/3Not Always Healthy A 'diet' is not always healthy; it's just a pattern of eating. Candy and soda made up most of his diet.