In 1981, Sen published Poverty and Famines: An Essay on Entitlement and Deprivation (1981), a book in which he argued that famine occurs not only from a lack of food, but from inequalities built into mechanisms for distributing food. Sen also argued that the Bengal famine was caused by an urban economic boom that raised food prices, thereby causing millions of rural workers to starve to death when their wages did not keep up.[17] However, this argument has recently been undermined by evidence suggesting significant decline in food availability in the Bengal Famine.[18] This implies the curious irony that Sen had bought into precisely the excuse used by the War Cabinet to refuse aid to Bengal -- that hoarding, not a lack of food, was the famine's cause.
Sen's interest in famine stemmed from personal experience. As a nine-year-old boy, he witnessed the Bengal famine of 1943, in which three million people perished. This staggering loss of life was unnecessary, Sen later concluded. He presents data that there was an adequate food supply in Bengal at the time, but particular groups of people including rural landless labourers and urban service providers like haircutters did not have the monetary means to acquire food as its price rose rapidly due to factors that include British military acquisition, panic buying, hoarding, and price gouging, all connected to the war in the region. In Poverty and Famines, Sen revealed that in many cases of famine, food supplies were not significantly reduced. In Bengal, for example, food production, while down on the previous year, was higher than in previous non-famine years. Thus, Sen points to a number of social and economic factors, such as declining wages, unemployment, rising food prices, and poor food-distribution systems. These issues led to starvation among certain groups in society. His capabilities approach focuses on positive freedom, a person's actual ability to be or do something, rather than on negative freedom approaches, which are common in economics and simply focuses on non-interference. In the Bengal famine, rural laborers' negative freedom to buy food was not affected. However, they still starved because they were not positively free to do anything, they did not have the functioning of nourishment, nor the capability to escape morbidity.