You can ask any athlete, or look up calorie expenditure charts for people carrying different weights if that more your thing.
I was a serious athlete for about fifteen years and still am casually. Of course it makes a difference; the question is how much. The answer is not much, especially when we're talking about relatively short distances (I don't think anyone commenting here is talking about carrying their laptop for a 30 mile hike), and I'd much prefer better battery life and the old keyboard.
Im not saying a pound of weight is much, I'm saying that our "rugged farming ancestors" certainly wouldn't scoff at carrying a pound less weight.
We're not farmers. If you are living under conditions like a farmer then yes, by all means, shed every pound you can. I don't imagine that the person who started this thread has to deal with those sort of conditions.
It seems I wasn't the only farmer to state this, as @lolsal said:
> When I'm walking my fields repairing my fences I absolutely wish my fencing tools were lighter, even if I'm using my truck or other vehicle to carry my tools. I don't think they'd belly laugh at someone who preferred more efficient tools.