Reference request: ON vs. empty calories?

[Guest guest]

On a mailing list of ultra-long-distance hikers I participate in,

we're having a discussion about whether a nutritionally-balanced

calorie (an ON calorie) is any more useful to the body than any old

empty calorie. I realize that this is more of a sports nutrition

question that a CRON question, but we're still talking about making

the most efficient use of the calories supplied to the body.

Anyway, can anybody out there cite any reputable sources that support

the idea that balanced nutritional intake results in more efficient

use of consumed calories? Or, is there a converse source which shows

that a mostly empty-calorie diet results in lower bioavailability of

nutrients?

Some long distance hikers who have successfully hiked several

thousand miles in a year have said things like: " On a trek like

this, it's not about natural, organic, nutritious, or flavorful...

It's about energy and your ability to fuel yourself with foods that

are palatable... If 'chips, chocolate, nuts, and soft candy' (or some

derivatives thereof) aren't your staple food source for extreme long

distance fueling then you need to rethink you're strategy, because

when you hit the wall, there simply isn't a whole lot of other things

you can force down. "

My own experience refutes this hands-down. But I'd love to have some

academic or authoritative sources to back me up.