Under-nutrition can be devastating and enduring, affecting cognitive development and future productivity - early intervention is critical...
"...Whether or not children are well-nourished during their first years of life can have a profound effect on their health status, as well as their ability to learn, communicate, think analytically, socialize effectively and adapt to new environments and people. Good nutrition is the first line of defense against numerous childhood diseases, which can leave their mark on a child for life. In the area of cognitive development, "when there isn't enough food, the body has to make a decision about how to invest the limited foodstuffs available. Survival comes first. Growth comes second. In this nutritional triage, the body seems obliged to rank learning last. (Sagan and Druyan)...."
A diverse diet rather than a grain-based mono-diet provides important building blocks for brain development, and also engenders better eating habits that protect the growing child from 1st world diseases like diabetes and obesity.
Hard to build a human computer on a diet of corn or wheat