I am always astonished to see climbers on a 2 day climb of Mt Rainier carrying 50 pound packs. It is uncalled for and outdated. For a 3 day climb on Rainier my pack weighs 29 pounds. I have friends go much lighter than this. It starts with your choice of gear. Following are a few companies that have supported my expeditions who make high quality gear. Quality that I trust at altitude in the Himalaya.
The Nalgene Canteen. It is the lightest water bottle on the market. It shaves at least 2 ounces off your load when using two 1 quart canteens. It could shave as much as 5 ounces off your load if you are using other brands. The canteen is durable and light, it is compressible when not in use.
I just received a 48 Litre pack. Most packs on the market that are 48 liters are 3 pounds and up. They have bells and whistles which only get confusing at altitude or are useless on steep technical terrain. Eliminate useless weight and stream line your pack with Figure Four Packs. Take a look at the Tau 48 by Figure Four Packs. 48 liters expandable to 55 plus liters weighs in at just 2 pounds 2 ounces and can be stripped down to 1 pound 7 ounces in the field in one minute. It is stream lined, it moves with you as you move, it feels like part of your body on vertical ground. It has everything you need for serious alpine climbs without all the extra weight.
I have been using a Feathered Friends sleeping bag since 2001. I just ordered a new bag from them and was very pleased to receive a custom bag that is a minus 10 degree bag and weighs only 2 pounds 14 ounces. For that warmth factor it is the lightest on the market. The quality is outstanding. Compare other bags with the same warmth factor and your looking at 3 pounds 4 ounces and up. I have never been cold in my Feathered Friends bag.
If you go through each piece of your gear you can find something that meets the demands of what you will be doing in the mountains but does not hold unneeded weight. Over the years I have shaved 15 pounds off of my back for a 3 day alpine climb.
Thank You Nalgen, Figure Four, and Feathered Friends.