It seems that malnutrition is now being linked to causing some problems with the brain. For example, those who are constantly not getting enough nutrition from the food that they eat may notice that their brain volume will decrease. They may have lesser working neurons.
There may be moments when they cannot recall things that they just did. Malnutrition can be most severe for children whose brains are still growing. If they are malnourished at this point, their brain growth may not be as good as other children who are getting proper nutrition. They may find it harder to cope in school and even in forming relationships as compared to other kids.