From the time of Malthus, the insufficient supply of food resources has been considered the main constraint of population growth and the main factor in the high mortality prevailing in pre-industrial times. In this essay, the mechanisms of biological, social and cultural nature linking subsistence, mortality and population and determining its short and long term cycles are discussed. The author's analysis examines the existing evidence from the century of the Great Plague to the industrial revolution, interpreting the scanty quantitative information concerning caloric budgets and food supply, prices and wages, changes in body height and epidemiological history, demographic behaviours of the rich and of the poor. The emerging picture sheds doubts on the existence of a long term interrelation between subsistence of nutritional levels and mortality, showing that the level of the latter was determined more by the epidemiological cycles than by the nutritional level of the population.