I have tended to lose weight: BUT NOT BLOODY ENOUGH!!
December in Provincia de Buenos Arires, probably meant I was just shrivelled from dehydration, but generally the smaller portions cooking on a camp stove, the more walking aroudn to see stuff, than I would back home: the not sinking in a sofa and watching the box, and the inveitable toiling with my GS in the sands all meant I shed a few calories on our bigger trip.
But even on small jaunts like my recent fortnight in France, I lost maybe 3 pounds (1.5kgs).
I never lost much more than a stone or so, though: 7 kg MAX in SA...
Probably the most expensive, but the most fun form of dieting I have ever experienced: beats the "celeriac & sand porridge" diet, or whatever is the fad at the mo'
Adventure: it's an experience, not a style!
(so ride what you like, but ride it somewhere new!)