When planning individualized diets for nine-year-old boys and girls, which approach best accounts for typical sex differences at that age?

• A. Provide identical meal plans to boys and girls because sex-based differences do not emerge until late adolescence, making individualized adjustments before puberty unnecessary and potentially confusing.
• B. Assign girls vegetarian diets and boys omnivorous diets to account for gendered activity patterns, because social trends automatically dictate different nutrient needs unrelated to physiological differences.
• C. Plan high-protein, high-fat diets for boys and low-carbohydrate, low-fat diets for girls to prevent early weight gain in girls, since girls are more sensitive to carbohydrates at age nine.
• D. Recognize that boys commonly have slightly higher energy and total nutrient needs than girls by around age nine, so tailor portion sizes and total calories accordingly while maintaining similar macronutrient percentages and ensuring both meet micronutrient needs like calcium and iron.

Answer: (D)