That was exactly the case on my 18 month bike trip in Alaska, South America, SE Asia & China. We found it very difficult to pack or even find enough quality proteins (and at the time we didn't know they where that important tbh). In the end I lost 20 kgs and went from 85 to 65 for a 178 cm 30 y.o. guy.

That was 5 years ago and I managed to mantain that weight by taking care of what I eat. I think that trip changed something in my metabolism and helped to know myself better.