In the previous chapter we examined models of the influence of fertility and mortality on the size of households. Two major (and quite deliberate) simplifying assumptions underlying all these models are (i) that fertility and mortality are exogenous to the household and (ii) that all households in a community are exposed to exactly the same demographic conditions. This assumption is patently false, even if it is convenient for some analytical purposes. Starting in the present chapter, we reverse the causality, asking whether mortality, fertility and migration differ among households owing to material conditions (especially those influencing food availability) that are peculiar to each individual household. Do all households in a community have the same level of, for example, early childhood mortality – and, if not, why not? I will argue that an important part of the answer is that feedbacks operate within the household involving food production and the household’s demographic life-cycle, and these feedbacks are powerful enough on their own to differentiate households even in the absence of clear social and political differences dividing the community as a whole. The critical linkage in this feedback, I believe, involves the relationship between dietary adequacy and various aspects of human physiology. If I am right about the importance of this relationship, it would point to a basic (and perhaps ever-present) form of population regulation operating at the level of the subsistence farming household. But before we can examine this claim, we need to review what is currently known about the relationship between dietary adequacy and the basic forces of demography – fertility, mortality and migration. And before we do that, we need to think more carefully about what we mean by “dietary adequacy” and how to measure it. This chapter does both. Because little of the evidence I marshal in this chapter is explicitly organized at the household level, households will play a somewhat covert role in this treatment. But, while contemplating the relationship between under-nutrition and, say, fertility or mortality, the reader should really be thinking about the role that under-nutrition plays as a potential impediment to the household demographic enterprise. Subsequent chapters return the household to center stage.