Hey photohiker,
I can't really answer, as I started 37 years ago, and my weight has changed a lot up and down in those years for reasons apart from bushwalking.
However, bushwalking has stopped me from becoming the size of a small house. I rely on multi-day walks to keep my weight in check. (I do them for plenty of other reasons too, of course.) I'm completely satisfied with the food I take with me, limited though it is, and I crave nothing. I've had lots of multi-day walks this summer, and my weight is now almost ideal, for the first time in about 30 years.
So there is a very significant relationship for me between weight and bushwalking, and 'none of the above' feels wrong.