Losing weight should be your primary goal and that should be done with lowering your calorie intake and adding exercise otherwise it will be hard to stick to. Then switch to foods with lower carbs as a follow-up effort. Avoid processed foods, avoid seed and vegetable oils, replace with extra virgin olive oils (regular & light), coconut oils or avocado oils. Pay attention to food labels and focus on "net carbs" (carbs minus fiber carbs) and limit to a max of 50g of carbs per day. Keep track of your blood sugar levels. I can't advise about the kids, so will leave that to others with related experience, but for yourself definitely it's about both losing weight initially then ensuring you are on a low-carb diet. No sugars, no corn syrup, sugar alcohol is an OK substitute but still spikes a little, avoid breads unless they are labeled actually keto, no pasta, no rice. For fridge/freezing foods the easiest thing is to think of "meats and vegetable" with minimal seasoning or sauces. I will often prepare a bunch of ground meat I put into a container in the fridge that I then add into meals over the next few days. For example, I will scoop some out and mix into my eggs in the morning, or heat some up and put into a wrap (low carb wrap bread) with some cheese. Lastly, fruit juice drinks and sodas should be avoided. The sugars in them are huge. Focus on water, coffee, tea, and find drink options in stores where the sugars are zero if you crave a flavored drink.
EDIT: For foods that don't come with labels at the store, do Google searches and keep a reference log for yourself. For example, fruits. Feed your kids what they want to long as it's healthy for them but for yourself if you're trying to control blood sugar levels then you really need to be aware that most fruits are high in fructose and the fibers that come with them aren't enough to avoid spikes. The only fruits I personally eat are blueberries, strawberries, raspberries and blackberries and an occasional apple and less occasional banana. I balance them with some nuts and whip cream topping to buffer the glycemic hit.
