PBA -“Health: I could also just put that canteen also in my backpack, where it would be easier to carry.”
Obviously, you could. And you could carry more water in your camel back. But I got the impression you didn’t want to carry more on your back. A small canteen elsewhere would not be a burden.
You seem to be looking for a Heter beforehand. I don’t think there is one.
But once a person is hiking and they feel hungry and the water they have is for drinking – esp. in hot weather -they should eat and drink without getting water to wash.
Why? Maybe they can make it to the next waterhole? Because once in this situation it’s a Sofek Sakana and you wouldn’t be allowed to wait. Yes, water alone is Not always sufficient to sustain you -you need calories (& lytes).
So try to carry extra water with you. If you forgot or miscalculated – you must eat and drink without delay.
Just clean your hands and don’t touch the bread.
I just saw a case of Heat exhaustion yesterday. And this is with electricity in town and a few feet from a house where he could have cooled off and taken in water and other stuff he needed. Instead he had to go to the hospital.
There is a reason it says “…Nafeshoysachem MEOD”.
“An ounce of prevention is worth a pound of cure.”