Sherlock Holmes IV and moi...

... are working on a monograph, trying to explain a correlation we've observed at the grocery store:

People who spend a lot of time driving around trying to find a place to park AS CLOSE TO THE DOOR AS POSSIBLE! also tend to be the same people who come out of the store with carts loaded down with junk food.

The question is: Which is the cause and which is the effect? I can see how someone who's got a few cases of beer and soda along with a few gallons of potato salad and chip dip might not want to have to push that load all the way out to the outer fringes of the lot (where Bob Uecker and I park).

I can also see how someone with that kind of diet might view walking ALL THE WAY ACROSS THE PARKING LOT! the same way most of my dear readers would view running an ultramarathon.

I've got Sherly doing most of the data collection since:
A) I'm kinda lazy when it comes to actual work, and
B) Sherly isn't exactly the darkest-haired guy in the bar, if you catch my drift, so it's best for him to do the grunt work while I deal with the logical analysis, a process I find rather elementary (or in this case, alimentary).

Related Questions:
1. Isn't "junk food" an oxymoron?
2. Will anyone get the "Bob Uecker" reference?