Hey K.,
This sounds challenging for you all but I am impressed you will be braving it. The best and easiest way for you to eat is to throw away the boxes and cans. Anything processed is going to be off your list.
We do meat and 2 veggies almost every night. This allows you to shake things up. Lemon and parsley are very flavorful and don't contain any sugar, cals, or sodium. You can marinate almost any meat in that or toss rice or quinoa in olive oil with lemon and parsley. Or lime and cilantro with black beans (rinse them if you're using cans to wash away the packaged sodium). Use herbs and citrus to flavor things and you will get great tasting stuff that won't make you all feel like you're suffering. Popular combos - Orange juice and tarragon, basil and tomato (use fresh), rosemary and garlic, lemon or lime with mint, green onions wake everything up.
Also sweet potatoes and winter squash taste sweet and help satisfy a sweet tooth. Plus fruit is an excellent dessert. You can also make smoothies for breakfast and we eat oatmeal without sugar in our house. Occasionally we'll use Stevia to sweeten it. A little goes a long way!
The other thing you have to do is read read read every label. And eat at home, foods you prepare yourself, as much as you can. Whole Foods has a wealth of things for you. But watch out - just because it's organic, or just because they sell it at Whole Foods does not mean it's healthy. You still need to read labels.
When in doubt make everything yourself. You can do this!
Good luck,
E.