I'm not suggesting that somebody try to survive _only_ by eating fruits and vegetables. I was suggesting eating them during the day when people would otherwise be eating potato chips and soda.
Speaking of ... as far as sugar overload is concerned, you'd have to eat three or four apples to match the sugar in a single can of cola, which has basically no nutritional value whatsoever.
In the spirit of this thread, they have zero preparation time, are easily accessible (keep them in a desk drawer, or on the desk), and have a lot of nutrients our bodies need. If you get high quality produce, it's also quite delicious.