Different parts of the world have different sorts of problems with food. For example, much of the rich world has a real problem with having too much food (and chemically contaminated food). This is why it is possible for over 30% of American adults to be obese. By contrast, other parts of the world lack food. For example, this article shows us that people in Kinshasa, Democratic Republic of Congo tend to lack food. They often have to go without food for entire days.
What this generally implies is that the world as a whole has a problem with the distribution of food. The world as a whole can produce plenty of food, but the food is not distributed in such a way that all people get enough to eat. This is a social problem with distribution, not an agricultural problem caused by an inability to grow enough food.