I generally lose 4-5 lbs while climbing a typical US or Canadian glaciated mountain. I wanted to find out if I was losing lean tissue as well as fat so I had a Bod Pod test done just before and after climbing Mt Baker and Mt Hood over a 7 day period. I lost 5.1 lbs of fat, gained 1.9 lbs of lean, for a total loss of body weight of 3.2 lbs. This is a pretty amazing result. I was surprised that I gained lean. Being an old guy, I was at 22% body fat before the trip. I don't know how much other data is out there, but is this typical? (Wish I didn't live on the East coast so I could do this more often)

I am not sure about what is typical, but I lost 15 pounds on a five day alpine climb once, but lost no weight on Denali.

Probably somewhat typical, but everyones bodies are slightly different. When I am in Peru or Nepal (unfortunately its been a few years..... really need to get back) in a 30 day period I'll loose an average of 15lbs starting out at 4-5% body fat (so for me its mostly lean muscle tissue). But ast 22% body fat I'd expect that you'd gain a little lean muscle while loosing quite a bit of fat (its a Joe Brown trick).

On what turned out to be an epic one day-ish push in the North Cascades I lost seven pounds. A couple of days later once I had rehydrated and eaten a couple of proper meals I was still four pounds lighter. Putting that in calories perspective if a pound of fat/muscle is 3,500 calories then it was a 14,000 calorie day. The only reason I remember this is because I was trying to lose a few pounds at the time.

Note that at the time I was a little over 200lbs and my best guess is 15-25% of "retained energy".

i lose weight during weeks i spend my food money on gas to go to the mountains but i guess this is different than the discussion here

EverydayExplorer wrote: then it was a 14,000 calorie day.

about the same as running 140 miles on level ground in a day.

I typically lose 10 or more pounds on an expedition and assumed it was all fat disappearing because I have a lot to spare. Never seems to last though

Also depends on what you define climbing as....

I didn't find a thread that fits my question but this one is close enough.

Some of this won't be exactly accurate but ........I have had many discussions about diets. The obvious is that if you burn more calories than you are taking in you will either lose weight or at least not gain. But many people who are always talking of diets speak to what is bad for you regarding weight gain. Most state it's calores and carbs. As I understand it, calories that ARE NOT from fat will burn easily if you are exercising. The same with carbs. As they turn to sugars, provide energy, and then are burned off. These "dieters" should be concerned with "fat grams" as they do not burn off as easily, especially if they are not active.

Is that basically the case?

I lose lots of muscle in my upper body and put on muscle in my lower body. I lost 15 pounds on Denali over three weeks, but could barely fit into my boxer shorts when I got back. My wife said my whole body changed.

Course, I usually crap a squirrel about a day or two after a climb, and that's 3-5 pounds right there... who knows, really?

It was 95% hiking with some scrambling, but in 2008 I lost about 5 pounds in 3 weeks of traveling and doing about 7 mountains over 14,000' with anywhere from 4000' to 6500' of change on each one. Got down to 150 pounds by the end of the session. In 2009, I lost about 2 pounds over 2 weeks on 5 mountain over 11,000' with 3000' to 6500' of change on each. Last year, I was stable, but the Grand Teton was my only real climb. Plus, I found, that if I had access to good food, like the Chuck Wagon in Grand Teton, I was more inclined to eat and enjoy meals so I didn't loose weight. In 2008 and 2009 I backpacked more to access peaks and lost weight, not so last year. I did a 5 day BP trip in May of 2010, but was stable, however that was more relaxation and the whole trip had only 4000' of elevation change. Plus, I ate a lot of cliff bars.

I would say alot of it depends on how much water ones body retains. Most of the initial weight loss is from sweating.

Heh, I will have some data as soon as I get home to my scale (from Colombian airport, yawn)

Smoove910 wrote:I would say alot of it depends on how much water ones body retains. Most of the initial weight loss is from sweating.

FYI- The fat/lean gained or lost from my original post was measured in a Bod pod which factors out the water content of the body.

I started on a long one day hike, weighing 152 lbs. The next day, I was just 69 kilograms.