This paper is a state-of-the-art of the major nutritional problems in developing countries. It shows that not only hunger (protein-energy malnutrition), but also iron deficiency and vitamin A deficiency are serious problems in the developing countries. 

The present knowledge on nutrition is much more detailed and sophisticated than is described in this working paper. In writing this paper I did not go into all the details because the Food and Agriculture Program at IIASA is working at a level of aggregation where these details have no significant impact on the ultimate results.