1) Malnutrition is defined as a cellular imbalance between nutrient supply and demand that impacts growth, maintenance, and functions. Severe malnutrition can be classified using weight-for-age, presence of edema, and weight-for-height measurements.
2) Identifying severely malnourished children involves weighing, measuring length/height, and calculating standard deviation scores. Mid-upper arm circumference less than 11.5cm also identifies severe wasting.
3) Severely malnourished children experience a physiological state called "reductive adaptation" where body systems slow down to survive on limited calories. This requires special treatment approaches compared to well-nourished children.