I notice that Kessilring cooks bannock with lard, and a fellow who calls himself "Wintertrekker" on youtube cooks with olive oil to obtain the benefits of a slow, even energy release, and to temper the up and down energy delivery of carbs-  especially simple carbs like sugar.
   Of course bears will' just kill' for fat in cooler weather , so the old timers practice of carrying a quantity of bacon or salt pork (close your ears,Mountenpaddeler ;D) is probably not that great of an idea , besides it's heavy. Peanut butter can get pretty bulky, and the only available fatty fish in canoe country is lake trout, and good luck with always coming up with those.
   So if your out for 4-5 weeks, or longer, super skinny  is probably a given ? That's good if you're carrying extra weight like am these days, but after a point,  it's not.
   Whadaya think?