This analysis is highly misleading. The cost of the labor involved, the amortized cost of the equipment, insurance, rent, etc. all need to be included in the price of the item. Nobody is charging a “400% markup” on ingredients; that terminology is imprecise.
When compared to the cost of making food at home, for example: it is not just the cost of the ingredients (which would be more expensive, because you can’t buy in bulk). You also need to take into acc0unt the value of the time you spend cooking and could be doing other things. If you could earn $10 an hour and you spend an hour buying ingredients and cooking them, that alone would put the cost of a home-made burger over the cost of your restaurant example.