Lots of great comments, let me throw in a few clarifications: This was for a 34 km (21 mile) day hike on Mount Rainier (not a summit climb), with about 1400 meters (4600 feet) of elevation gain. Total dry weight (without H2O/Gatorade) = 6.5 pounds. We started out at 4:20 am, so headlamp was used going out. I’ll…