Wasting, kwashiorkor and stunting are not usually due to either protein or energy deficiency. Treatment based upon this concept results in high mortality rates, and failure of treated children to return physiologically to normal. They become relatively obese with insufficient lean tissue. Preventive strategies have also failed. Wasting and stunting are primarily due to deficiency of type II nutrients and kwashiorkor probably due to deficiency of several type I nutrients that confer resistance to oxidative stress. Modern dietary treatments are based upon the F75 formula whilst the child is sick without an appetite, followed by F100 for rapid gain of weight. Derivative, ready-to-use therapeutic foods (RUTF) allow treatment of large numbers of children at home, are preferred by mothers and dramatically improve coverage. Children are indentified by screening in the community and treated before complications arise, using simple protocols. Successful treatment of the sick children with severe malnutrition not only depends upon these products, but appropriate management of complications. The physiology of the malnourished child is completely different from the normal child and many drugs and treatments that are safe in children with normal physiology are fatal for the malnourished child. In particular, the diagnosis and management of diarrhea and dehydration is different in the malnourished child. Giving standard treatment frequently leads to circulatory overload and death from heart failure. The challenge now is to find successful local ways to prevent malnutrition and achieve nutritional security. Until prevention works, we have to rely on fortified foods for treatment and convalescence from illness.