Being healthy and fit is important for achieving goals in life. Nutrition involves understanding the role of nutrients like proteins, vitamins, and minerals in body growth, development, and maintenance of health. Dietetics applies the principles of nutrition through meal planning to promote wellness for both healthy and sick individuals. The document discusses that protein, carbohydrates, and fats provide energy and their metabolism contributes to energy requirements, while also noting that fats should provide 20-30% of dietary energy intake according to WHO recommendations.