A severe deficiency of all nutrients, categorized along with other protein energy malnutrition disorders. Marasmus, which means "to waste" can occur at any age but is most commonly found in neonates (children under one year old). Starvation resulting from marasmus is a result of protein and carbohydrate deficiencies. In developing countries and impoverished populations, early weaning from breast feeding and over dilution of commercial formulas places neonates at high risk for getting marasmus.

Because of the deficiency in intake of all dietary nutrients, metabolic processes--especially liver functions--are preserved, while growth is severely retarded. Caloric intake is too low to support metabolic activity such as protein synthesis or storage of fat. If the condition is prolonged, muscle tissue wasting will result. Fat wasting and anemia are common and severe. Severe vitamin A deficiency commonly results in blindness, although if caught early, this process can be reversed. Death will occur in 40% of children left untreated.