It doesn’t matter where you live in the world and what your culture is; adults need to eat about two thousand calories a day. Due to famines in some parts of the world, some people may be forced to eat less but this isn’t sustainable. The amount people need to eat isn’t influenced by national or cultural needs. The type of food may vary from country to country but the basic premise stays the same. Adults need about two thousand calories to maintain a healthy lifestyle.
The premise that people consume the same amount of calories all over the world means that one should be able to calculate the number of calories which need to be produced/grown by counting the number of people. To put it another way. Global food production is directly related to global population.
When the number of people increases, then they need more living space. This involves the conversion of arable land into villages, towns and cities. Since there is less arable land available for food production, this could result in food shortages in the futures. This coupled with potential environmental impacts like flooding / drought means that acts of god can have a huge impact on the amount of food available for consumption.