A variety of factors are believed to have caused and contributed to the famine, including successive seasonal droughts, requisitioning and confiscation of foodstuffs by occupying armies, speculation, hoarding, war profiteering, and poor harvests.

In November 1915, the price of one kharvar (100 kilos) of wheat increased to twenty tomans,[clarification needed] "if there [was] any to be found", after the total granary of the south-east province of Sistan was sold off to the British troops.

By early February 1918, the famine spread throughout the country, and panicked crowds in major cities began to loot bakeries and food stores.

Thus, for example, the printing-house workers, who had recently formed a union, staged a demonstration in Tehran in 1919, during which crowds attacked the bakeries and granaries, and called on the government to increase food rations, to standardize the price of bread, and to regulate the quality, supply and sales of foodstuffs.

[2] The colossal food crisis, plus large numbers of soldiers, refugees and destitute people constantly on the move in search of work and survival, facilitated a deadly combination of pandemics and contagious diseases.

[2] The 1918 flu pandemic spread to the entire country via three main entry routes: Transcaucasia to Tabriz, Baghdad to Kermanshah and India to southern Iran (the latter significantly vected by the British Indian Army soldiers stationed in Bushehr).

[4] Afkhami states that the flu impact was enormous and estimates that between 902,400 and 2,431,000 or 8.0% and 21.7% of the total population died, making Iran one of the most devastated countries worldwide.

[10] Tammy M. Proctor comments that the cause for food shortage was a combination of army requisitioning, war profiteering, hoarding and poor harvests.

[17] Scholars such as Ervand Abrahamian, Homa Katouzian and Barry Rubin maintain that the total death toll due to starvation and disease was around 2 million.

[27] Abrahamian comments that Majd's book includes an "exaggerated discussion" of losses during the famine,[28] a view he shares with Mahmood Messkoub,[29] Abbas Milani[30] and Rudi Matthee.

[6] Abrahamian describes calling the famine a genocide as "wild accusation" and attributes the vast majority of the 2 million deaths he estimates to cholera and typhus epidemics, as well as mostly worldwide influenza pandemic.

"[32] A similar view is expressed by Alidad Mafinezam and Aria Mehrabi, who state that Majd's work suffers from methodological defects, including lack of triangulation.

[34] Siham al-Dawlah became chief of the bakery bureau (raʾīs-e nānvāʾī) in 1918 and an alimentation committee (komīté-ye arzāq) was also formed out of seven or eight influential merchants.

[41] The official website of Ali Khamenei, Iran's supreme leader, published an article in 2015 asserting the view that the famine was a deliberate act of genocide committed by the British, whose documents have been intentionally wiped out in a cover-up attempt.