A healthful diet includes balance; variety; and which principle?

A healthful diet is characterized by balance; variety; and moderation. Moderation involves consuming appropriate portion sizes and avoiding excess; ensuring nutritional needs are met without overindulgence. Availability; quality; and complimentary are not standard principles in dietary guidelines. This question emphasizes nutritional science; and moderation is a key concept in promoting long-term health; making option B the correct choice.