The nervous system develops in utero and during infancy and childhood, and in these periods it is vulnerable to macronutrient deficiencies. As a rule, general malnutrition among adults does not cause specific neurological damage, whereas among children it does. Undernutrition can be assessed most commonly by measurement of the body weight and the body height. With these two measurements, together with age and sex, it will be possible to evaluate the energy stores of the individual. Nutritional issues are highly common during the course of neurological diseases, potentiated by the eating and swallowing disturbances accompanying the clinical picture. Stroke, acute and chronic neuromuscular diseases, and chronic neurodegenerative diseases are the most common neurologic disorders linked to swallowing problems and malnutrition. Malnutrition, if present, increases the morbidity, length of hospitalization, and mortality over the course of these diseases. Maternal malnutrition can result in both global and specific neurodevelopmental sequelae. Children of underweight women are reported to have an increased risk of delayed mental development. The hippocampus (memory), the cortex, and auditory development are particularly vulnerable to malnutrition in early pregnancy. Other effects of early intrauterine malnutrition only become apparent in later life, and include adolescent and adult problems, such as attention-deficit disorder, conduct problems, and eventual low socioeconomic status.