I used to travel a lot for work and would often use the time away from home to slim down. I was usually in a hotel with a nice workout area which was a nice bonus.
Up early, hit the gym, eat some fruit. Work, work, work...eat a salad, go for a run, go to bed. Do the same thing for 5 or 6 days and I would fly home with looser pants.
Work travel often sucks monkey ass. I know it did for me. So, it is a good time to focus on something really positive like health and fitness.
And that per diem can be a nice perk for the stash.
Good luck!