Robin start with understanding calories required.
In this chart please note that they consider ‘active’ as ‘Active means a lifestyle that includes physical activity equivalent to walking more than 3 miles per day at 3 to 4 miles per hour, in addition to the light physical activity associated with typical day-to-day life’ ……and add more for SHTF type work. Stress alone burns lots of calories.
Then know which foods provide the most calories and stock heavily in those: oatmeal, rice, wheat (the products you make with them) , and peanut butter, dates, coconut milk, cheese, meat, chocolate and oils I think are high in calories and not too bad for your health. Then add all the other stuff to go with it.
Working a very small farm now, I burn calories. But, haha, don’t need to pay for a gym membership either.
The best I have ever read, and from my experience I agree, is this post and inventory list from Granny Miller of her food storage list. True, she – like me – grows/raises and cans/processes most of her own storage – but I think it would give you a place to start. Each family is different in what food they like. But if you have calories in mind and read her post/look at her list and add/subtract and adjust it would be a good place to start.
If you eventually want to grow and process some or all of your own food – her chart on how much to plant for a family of four of different vegetables etc is invaluable.
She has been living this life and doing this for years – being self-sufficient as possible. Her blog will keep many people occupied for hours.