With all humility, I am looking to solve a problem that has plagued a number of my hikes. I am not looking for detailed bio-physics of the human metabolism as I have seen in other threads. I can't follow all of that stuff. :) I am just looking for some thoughts on what you think the cause is and what I might try.
So here goes:
I tend to over exert myself on the trail. Generally speaking I do 15-20 miles a day (which is a lot for me) and the uphills pretty much kill my legs – but I press on. Shortly into my hikes, I lose my appetite for food – even for the most decadent candy or junk food. Then comes the nausea. Generally speaking this makes me even less inclined to eat or drink anything which probably compounds my exhaustion and nausea even further.
Usually it doesn't get any worse than that. I stop hiking for the day, the nausea goes away, but I take in very little in the way of calories because I just don't feel right until the next morning. Sometimes, however, if I eat anything solid shortly after or during a hard hike, I will throw it up. I can, however, continue to hydrate without a problem but still remain nauseous until I have had a significant rest (usually overnight) but still not much of an appetite.
Obviously this issue causes me to become further dehydrated and leads to a very unpleasant hiking experience.
My thoughts are that I am either not hydrating enough or not taking in enough carbs for the activity I am engaging in, but there's the rub – I nauseous and don't want to eat.
Thoughts on what might be the issue and what I can try?

