This must be the most profitable item sold in shops.
I suddenly realized that this is what I was paying when I bought a piece of fish in a local supermarket and a very thin sheet of plastic was put on the scales the fish placed on top of it weighed then priced.
When I pointed this out to the shop assistant he said that "it didn't weigh anything"! I suspect this item that weighs "nothing" is purchased by the ton.
I occasionally fish for Rainbow trout in a local lake. Example of price is £35 for 3 fish. With luck the gross weight is about 7.5 Kg for 3, so after gutting etc, maybe a nett cost of £9 per Kg. That does not include my car cost, depreciation on fishing tackle, a couple of artificial flies nor my time!! All in jest of course but a different angle (!) on the issue.
OK you need a bit of fat but what makes me gag is when you see the fat still white and basically uncooked especially when TV 'Chefs' cook it. I like the pork fat cooked till it starts to render and loses the raw look, even better if its a bit crispy. I saw lamb chops on TV the other day with white uncooked fat and red raw inside. I don't mind it a bit pink but still raw NOT! Can't understand the trend to eat meat almost raw these days after all cavemen discovered that it was much nicer cooked.
Most electronic Scales are only accurate to + or- 5 grams
I'm pretty sure that commercial/retail scales need to be much more accurate than that and have to be tested and calibrated. I know when I worked that the scales used for Average Weight recording of our production were Laboratory type and very accurate.
Even my Kitchen Digital scales read to 1 gm. I'm not sure of their accuracy as obviously they aren't calibrated but they are reproduceable.