I think you need to include energy cost in the preparation stage. Bread requires a hot oven, which is a real amount of electricity — it’s close to $0.40/kWh where I live. From this link it says that a bread maker uses only .36kWh, but an electric oven would be more like 1.6kWh. So bakita single loaf of bread, you end up with a not insubstantial fraction of the total cost going to heating the oven.
Of course, many bulk foods require heat, so it gets a little sticky this way. Oats/oatmeal probably wins out here, as you can just soak them overnight.
The only flaw in Corel’s logic was that as soon as you’re running Linux, you lose all desire to run WordPerfect, and develop an irresistible need to align yourself with vim or emacs…