There is no right answer to this question, if I had to, and when I had to, I could live frugally (spaghetti hoops on toast being a dinner !) . I consider food one of the joys of life and I haven't a notion of living frugally. The older I get and particularly due to Covid that is my view. Our actual food bill is higher due to Covid but we are saving a fortune on dining out. And we dined out very well indeed.
Maybe a better question should be how much can I get the food bill down to, for those needing to do so. Without feeling like the family are hard done by.