Malnutrition is a condition that develops when the body does not get enough nutrients and energy to ensure growth, maintenance, and bodily functions. It can be caused by lack of breastfeeding, overcrowding, ignorance, poverty, infection, and closely spaced births. Risks include diarrhea, electrolyte imbalances, growth retardation, mental retardation, hypoglycemia, dehydration, and infection. Treatment involves resolving life-threatening conditions, restoring nutritional status, and ensuring rehabilitation through a three-stage process of hospital care, dietary management with local foods, and supervised nutritional training for mothers.