Oh yeah, there's nothing like trying to teach a CHFer that canned soup is unhealthy then remembering that I ate a bag of cheetos ofr "breakfast"
I do mostly private duty now and try to pack a good lunch to eat during the shift, generally I can use the client's fridge and microwave. Also always keep a non-perishable food in the car like a can of (vegetarian) "spaghetti-os" for those days that I'm on my way and realize I forgot to grab my lunch!
For days that I travel more, I like to pack fruit, fresh cut at home or packaged snack cups occasionally. Applesauce, apple slices and peanut butter, carrots and dip, nutty trail mixes. I do buy the deli made sandwiches at gas stations, etc but can get expensive. If I ate meat, the cheaper way to go would be grocery store subs, but who wants salty cold cuts all the time, either?
Try a good cooler, one that will hold a sandwich or salad as well as a few cold packs and your drinks (start out with one juice or water bottle cold, the other frozen) Maybe a cooler that plugs into your cigarette adaptor would work, too? But if you're like, me your adaptors are already full!
I like to keep track of where the neighborhood parks are, I can often swing 10 minutes in the parking lot for the hardest to manage part of my lunch and eat the easy finger foods on the road.