Abstract
The advantages and limitations of using functional methods are discussed in the context of identifying undernutrition and hunger in children in the United States. At this time many of these methods have been used only in developing countries where undernutrition is more serious. However, there is great need to investigate whether, when and how undernutrition in the United States affects children's development. Functional measures can detect undernutrition and hunger in some situations where biochemical or clinical measures cannot.