Possibly over a million people died in the 1974 famine in Bangladesh from July 1974 to January 1975, although the Bangladesh government claimed only 26,000 people died. The causes are generally thought to be a combination of natural disasters (cyclone, droughts and floods).
Among the socio-political factors, Devinder Sharma of the Global Hunger Alliance claims that:
At the height of the 1974 famine in the newly born Bangladesh, the U.S. United States had withheld 2.2 million tonnes of food aid to ‘ensure that it abandoned plans to try Pakistani war criminal.
Here is documentary by John Pilger which depicts the tragedy and the US politics behind this.