This paper draws on four bodies of literature to consider the determinants of healthy eating for low-income Canadians: a) the social determinants of health; b) socio-economic gradients in diet; c) food security; and d) the sociology of food. Though there is a paucity of data for Canada, it is very likely that, as in other industrialized countries, there are socio-economic gradients in diet such that those who are better off consume healthier diets than those less well-to-do. The available evidence suggests that income affects food intake both directly and indirectly through the dispositions associated with particular social class locations. Thus, there may be both economic and cultural thresholds for some food groups or particular foods in food groups. Understanding these thresholds is especially important in addressing the issues facing those who are the most vulnerable among Canadians with low incomes: the food insecure. The literature reviewed suggests that improved nutrition for low-income Canadians may be difficult to achieve a) in isolation from other changes to improve their lives; b) without improvement in the nutrition of the general population of Canadians; and c) without some combination of these two changes. Four major areas of research need were identified: a) national data on socio-economic gradients in diet; b) sociological research on the interaction of income and class with other factors affecting food practices; c) sociological research on Canadian food norms and cultures; and d) research on the costs of healthy eating.