And what if the vertical farm and office building idea were combined, so that you had alternating floors of greenhouses for plants and office workers that ate them?
It takes 1-2 acres of farmland to support one person's eating requirements, which is two floors of the Empire State Building. Alternatively, there's 21000 people working in the ESB so that's about 200 people per floor. If you devoted every second floor to agriculture (and magically solved the lighting problem) then each worker could acquire 0.25% of his daily caloric requirements from the floor below... maybe a couple of strawberries?
Oh, and the ESB rents for $38 a square foot, so working out the effective cost of each strawberry is left as an exercise for the reader.