In the second half of the 20th century it became obvious that a relentless increase in diabetes type 2 (DM) affecting the economically affluent countries, is gradually afflicting also the developing world. This review juxtaposes the threat that the DM epidemic represents to mankind, with the astonishing recent discoveries on the role of obesity and of the body fat in this metabolic disorder. Presently, the highest prevalence of DM is in Saudi Arabia, a country deep in riches generated by its oil wells. DM is very high, in over 10% of adults in the USA, Switzerland and Austria. Prevalence is low in Norway, China and in Iceland. Predictions of epidemiologists for the first third of the 21st century claim up to 2.5 times increase in DM in the Middle East, Sub-Saharan Africa, India, rest of Asia and in the Latin America. In China the number of patients with DM will double but in the economically advanced countries that experienced rise in DM in the 20th century, the increase will be only about 50%. Remarkably, a lowest increase in DM is expected in the countries that formerly belonged to the Soviet political space. Increasing urbanization, aging populations, obesity, and falling levels of physical activity are all contributing to the rise of DM worldwide. The main cause of DM pandemic is growing prevalence of obesity, in Europe and in the Latin America. In the North America obesity is considered to be responsible for 90% of DM in females. Male obesity is associated with DM slightly less, at 70-80% in the European Union and in the US. The precise mechanism by which obesity leads to insulin resistance and to DM is not completely described but it may be related to several biochemical factors, such as abnormalities in free fatty acids, adipokines, leptin and other substances (Tab. 1, Fig. 4, Ref. 24).