Hello there, Aacey!
Well, I'm not a nutritionist, by any means, but my family has had a tradition of fairly healthy camping foods that may help you out.
What we normally do is take a bag of mixed veggies along with us in the cooler; broccoli, squash, red potatoes, bell pepper, onion, etc. For seasoning, bring along a spritzer of "I Can't Believe it's Not Butter", and maybe some S&P, or Mrs. Dash. To cook them, you can use aluminum foil to wrap the veggies in for cooking over the fire. Spread the veggies over one sheet of foil, add a little bit of water for steaming action, and then sprinkle on the mrs. Dash or S&P. Fold the ends up around the veggies, so it makes a little bowl. Cover the top of the veggies with another piece of foil, and twist the top and bottom pieces together, so the veggie "bag" is sealed. Throw the foil over the fire, and let them cook for about 10-15 minutes, or so - or until they are tender, to your liking. Once done, unwrap and spritz with the fake butter - and there you have a healthy, low cal, no fat portion of the meal! Filling and delicious!
You can do the same foil trick with fish, as well (minus the water). If your family is going to an area in which you can catch your dinner, it's a great way to fix up the fish. Just bring some extra foil, a bit of olive oil (or unsalted butter), rosemary, lemon and S&P - drizzle and wrap the fish, cook it over the fire for about 15-20 minutes, and you have yourself a great piece of fish to go along with the veggies.
Even some pre-made veggie and chicken or shrimp skewers would be an awesome idea to place in your cooler and take along on your trip Bring some Worcestershire or teryaki sauce, and brush the skewers with it as they cook for added flavor.
For breakfast, I tote with me the individual packets of regular, non-flavored instant oatmeal, and either mix in a cup of the Del Monte peaches in light syrup, or just a bit of peanut butter with blueberries. You just heat up the water on the fire, mix it in the oatmeal, put in your flavorings and it's done. Another cool breakfast idea I discovered recently was in Costco, and your whole family may live it! It's called "Batter Blaster" and can be found in the refrigerated section. It's an aeresol can of pancake batter! It's SO easy, because it's pre-mixed, and all you have to do is squirt it into the cooking pan! Serving size is 1/4 of a cup, and is about 112 calories, with only 1 gram of fat, I believe. Make yourself two of those pancakes, add some strawberries or blueberries and sugar free or light Cool Whip - and there you have it!
Snacks I always bring apples, Nature Valley granola bars, baby carrots and beef jerky; all virtually low-cal, and durable enough to withstand a few poundings in the back pack! Plus it is a variety of foods, so things don't get boring.
When my husband and I are away from home and camping or hiking, I always make sure to plan the meals a bit on the low-fat side, in case I forget to take my pill amidst the fun! Nonetheless it is still low cal, so even if you do forget your pill, you already have planned the meal, you know what to expect, and you are not "falling off the wagon", per se. You can still enjoy your vacation, and still stay on track - so there's no worries!
Hope this helps! Good luck and have a great time!