Nutrition Requirements and Growth
This domain tests how you translate age, sex, activity, and clinical status into energy, protein, fat, and micronutrient needs - and how you interpret growth velocity over time.
Core rules
- Energy: use estimated energy requirements by age, sex, and activity. Infants need high energy and protein per kilogram; requirements per kilogram decline with age. Do not apply adult formulas to children.
- Protein: highest per kilogram in infancy; increase for catch-up growth, burns, dialysis, or malabsorption, but avoid indiscriminate high-protein prescriptions.
- Fat and carbohydrate: fat provides 30–40% of energy at 1–3 years and 25–35% at 4–18 years; carbohydrate about 45–65%. Include essential fatty acids.
- Micronutrients: iron-fortified foods from about 6 months, vitamin D supplementation for breastfed infants, and attention to iron, zinc, calcium, and B12 in restricted diets.
- Growth: track weight velocity, length velocity, and head circumference. Crossing two major percentile lines downward is a red flag.
Worked example
A 3-year-old drops from the 50th to the 10th weight-for-age percentile after an illness while length stays at the 50th. This is acute weight faltering. Estimate energy needs using the age-appropriate requirement plus a modest catch-up allowance, use small frequent energy-dense meals, treat the underlying cause, and recheck weight in 2–4 weeks. Avoid aggressive overfeeding.
Traps
Overfeeding during catch-up; using adult protein or energy equations; excessive juice displacing food; missing iron or vitamin D deficiency; ignoring growth velocity because one percentile looks acceptable.