Up until 1800, Malthus was spot-on -- any advance in technology that was greeted by population increase would snap back to an equilibrium, with war|disease|hunger inflicting the correction. Gregory Clarke goes into great detail, with statistics on caloric consumption, lifestyle, etc.. that show that the average person at the pre-dawn of the industrial revolution did not experience conditions much more favorable than those of Roman times.

http://www.princeton.edu/~pkrugman/malthusian.png