Does the world agricultural system produce enough food to feed the current world population of approximately 7 billion persons? How many total kcal/year and how much protein, fat, and carbohydrates does the world agricultural system produce? As the world population continues to rise, will there be enough food for a population of billions more persons?
If we assume 2740 kcal/person-day, that value is one million kcal/person-year (1.0E+6). The top 50 staple crops in my analysis (Comparison of World Staple Crops — PDF summary here) produce 1.044E+16 kcal/year, which is enough calories for 10 billion persons. So the world agricultural system does produce enough calories.
However, the same analysis shows that the top 50 staple crops only produce enough dietary fat for 6 billion persons: 1.82E+15 kcal/year from fat. With a diet of one million kcal/year, and 30% of calories from fat, the total kcal from fat needed by 7 billion persons is 2.10E+15, and the total for 6 billion is 1.80E+15. The world agricultural system produces enough kcal for 10 billion persons, but only enough dietary fat for 6 billion persons.