Half-baked idea

SO we’ve started thinking about actually planning out our meals for the week before we go grocery shopping. Think about this and you realize that there is a lot of information management involved. You pick a recipe for each meal, break the recipes down to their ingredient lists, add up all of the ingredients for all meals, sum up the quantities, subtract what you already have in the pantry and finally you have your shopping list.

Computers could help here, couldn’t they? We haven’t used an online grocery site in quite a while, but as far as I recall the interface was a recapitulation of the brick and mortar version (food categories, aisles, etc). That seems wrong to me. I want to pick my menu and have the server generate my shopping list from it. Do any of the online grocers do that now?