What is the fine-grained topic of the following text: Considering our lives have also become more sedentary over the years, and that most people are supposed to eat between 1,800 and 2,200 calories a day, is it possible that the sheer extra number of calories produced by our food system could be partly responsible for the extra number of inches being tacked on to our waistlines? Only return the topic.
The impact of increased food production on obesity rates.