With your reaction to the pria bars, I woudl say stay away from the Atkins bars as well. Pack yourself a lunch. Have nuts in the car or other places for an emergancy lunch.

I would also recomend having more veggies then maybe just some at dinner. Try fried cabbage or an omlette made with mayo and spinach filling. Have a large salad for lunch with sliced egg and diced chicken breast. Ect. The veggies will not only add nutrition and regularity, but also help you feel fuller. They are also a good way to add aditional fat in the forms of butte ror other mix (such as coleslaw) or a good way to reduce calories if you are going that direction.

You can get a small cooler for the car if you are going to be gone multiple days. If you are home at some point in the day though, pack fresh snacks. Ziplock has snack size bags that work great for this. Get celery stuffed with laughing cow or peanut butter. A hard boiled egg and string cheese are also good snacks. IF you use store mayo tuna salad, chicken salad, or coleslaw can safely stay in a lunch box until lunch. Try packing a small plastic container of ranch dressing, then have things to dip into it like celery sticks, sliced cucumber, broccoli and so on.