Carbs and calories are your two biggies, and of course protein to help avoid muscle loss, and fats have various roles for hormonal production, slowing of protein digestion, etc
Exercise I dont do other than weights, I dont do any cardio and I dont want to. If I do any at all then I prefer walking, for up to an hour a day which puts me about 4.5 miles around a certain lake nearby.
If you want to go that route, then cardio HIIT or standard on an empty stomach in the AM is the typical way of hitting fat stores as best as possible, just make sure to load up when you return home so you aren't continuously in a catabolic state.