Putin says U.S. is "parasite" on global economy
Let's say you have country A and B
Both of comparable population and land size.
In country A, most of the people live on small farms where they raise most of their staples themselves and barter with neigrabroadors for the rest.
In country B, most of the people live in cities and buy their food from the grocery store.
About the same total amount of food is consumed in both countries but country B has a much higher GDP because of all the grocery store's added value.
Sense, this makes none.
And before you try to tell me this is too gross of a simplification, go check your wiki pages and see when GDP was invented.