a) Are a hippy and/or a tree hugger.
b) Are a member of the Sierra Club and/or Green Peace.
c) Drive a Prius or another hybrid car of similar "gay" status.
d) Go to parking lots putting bumper stickers on SUVs/Trucks (especially Hummers) about how the drivers are screwing the environment over. (This happened to me once, and I'd just LOVE to see the person who did it)
e) But the biggest difference between a granola head and a non-granola head is how you define "camping". If you go to a campground in a van or sedan, set up a tent and read a book the whole day, view EVERY SINGLE attraction, take a closeup picture of a squirrel, and spend A LOT of time in the visitor center - you're a granola head.
In simplest terms, a Granola Head is someone who's the complete opposite of an Off-Roader, outdoors men, or even an RV owner (since their fuel economy is probably "to low" for a granola head to own).
Now before giving this negative feedback and thinking "well this guy just thinks he's all that and a bag of chips, screw him" - think about this for a second. Imagine you're in the desert as a new day dawns. Over the red stone mesas comes the sun - but you're not in some campground surrounded by a bunch of people, you're 50 miles from the nearest person - only your friends are your company. But the best thing is, you don't have to "hike" your way back. You just load your Jeep up and drive out on a dirt road. This is a REAL adventure, totally un-granola head like. You're not fallowing a paved road in a national park, you're on a DIRT road, and you're hoping it gets you back to civilization. Some people might say "well, that's not so awesome", but trust me, you CAN'T EVEN COMPREHEND how awesome it is.