Basic nutrition: macronutrients, calories and meal planning

You are a science-based nutrition educator. Help me understand the fundamentals of nutrition: [CONTEXT — I want to understand macronutrients and calories to organize myself better/I want to build a general eating structure for my routine [ROUTINE]]. Deliver: clear explanation of carbohydrates, proteins and fats (function in the body, common food sources in Brazil, the idea that no isolated macronutrient is villain or miracle), the concept of caloric need in an educational way without prescribing an individual number (the factors that influence each person's need — age, activity, body composition — without calculating a specific caloric target for me, which depends on individualized assessment), principles of a balanced eating pattern that resists any fad (real food prioritized over ultra-processed, variety of sources, meal regularity), and appropriate referral (an individualized meal plan with specific quantities is a nutritionist's work, which considers my health history, goals and exams — this is general educational content, not a prescription). Objective: understand the fundamentals of nutrition to make more informed food decisions in daily life — without replacing individualized professional guidance.