Pack a personal filtration water bottle to filter out all the nasty bacteria in local water and turn it from contaminated to clean. Try to pencil in 10-15 minutes each morning and head over to Youtube for free daily workout videos, like yoga or pilates. Give your gut a head start and invest in some good quality probiotic tablets.
Packing your first aid kit pre-travel. Yes, there are pharmacies in all countries but they might not have the medicine (or brand names) you’re used to or a language barrier.