Their argument aside, I really do keep a lot of food on hand. I stock up when groceries we use are on sale. I buy in bulk. I refresh the supplies before we are fully out. And, using what we have on hand, I make varied and nutritious meals every day. When I say varied, I mean varied in the outcome, not necessarily varied in the ingredients. For example, I don’t buy a big variety of proteins; ground beef and ground turkey, chicken, eggs, beans, and sometimes pork (roast or chops) about covers it here. But there are hundreds of main dishes I can make using one of these proteins as the starting point.
In the pantry, I keep: various flours and sugars, oats, whole wheat berries, pastas of many kinds, rice, taco shells, powdered milk, dry beans, barley, canned tomato products of all kinds, canned beans, corn, and mushrooms, canned tuna, chicken, and roast beef, canned fruits of several kinds, juice sometimes, dried fruit, jams, broths, mushroom soup, tomato soup, canned milk, honey, molasses, nuts, popcorn, graham cracker crumbs, cake mixes, jello and pudding mixes, chocolate for baking, shortening, sprinkles, and a wide variety of condiments, vinegars, oils, and seasonings. Now and then I buy cereal, crackers, chips or granola bars, but only when they are dirt-cheap.
The refrigerator usually holds: leftovers, milk, fresh fruit and veggies, eggs, cheese, yogurt, sour cream, meat to use this week, lemon juice, margarine, corn meal, sourdough starter, ice water, and condiments and dressings.
With such a stock of food on hand, rarely have I had trouble deciding what to make for dinner. So I see no reason to plan menus every week.