Excellent article, lots of valuable detail.
Weight loss is a fact of life on longer backpacks, you've documented why.
That's for the most of us that pack it on in the non hiking season. What about for very fit, not overweight, trained backpackers?
I's like to see analysis of the changes in appetite and taste in long hiking, as well as hydration and electrolyte depletion. What works for marathon length running is different yet. What about that 7 to 12 day, all 15 and 20 mile day Sierra backpack? Ultralight gear and poles means most of us can do that if we train a bit for it. What is needed nutritionally for this kind of thing? Very little in print besides generic truisms and I read everything I can find on these subjects. I need to research articles on adventure racing. See what they know.
Using hiking poles is essential especially if it's at all hilly, mountainous, Sierra-like. I guestimate a 20% range increase with poles. Sorry doubters, there is a huge advantage to poles. I finally went for the expensive carbon fiber poles from backpackinglight.com. No regrets.
I was astounded by your mention of Nordic Walking. I've taken 2 Saturday classes with the trainer mentioned in the L.A. Times article. She is Malin Svensson. Site is: http://www.nordicwalkingusa.com/
She is affiliated with the Finnish originator International Nordic Walking Association or INWA. There are several entrepenurial startups on the web with similar initials which seem to be entirely homegrown efforts, offering gear and training. Value of these is unknown, so caveat emptor.
Nordic Walking uses several remarkable techniques new to me as a long time pole using backpacker. If there is interest I'll be more specific. Of course, I'm just seriously starting it now. I am very excited about NW, certain already that it will be my primary year-round conditioning and training activity. It beats running, biking, swimming and gym machines by a thousand miles for total fitness and preparation for hiking and backpacking. It's far more demanding than it looks!
Like other poling or "Nordic" sports you have to get over that self-conscious pole phobia to do it. Not so hard to do, it's a kind of test of self-determination in itself. In 10 years no one will even look. It's coming.
Best, Todd in Cat City. (Cathedral City, nothing to do with cat food cans.)