Availability of food across countries

Food is a basic human need. And we tried to estimate how much do people pay for food in different countries. It appeared that food availability significantly varies across countries. In general, price of 1000 Kcal goes up inline with per capita income. For example, in Greece, Belarus, Croatia, Japan and Macedonia people pay $2.8 (based on PPP) for 1000 Kcal. At the same time in Nigeria, Uzbekistan, China India and Kenya the price of 1000 kcal is less then $0.7. It is interesting, that the U.S. citizens pay for food noticably less compared to other developed and many developing countries.