But it is not a law here and if you go grocery shopping everything is printed in English and in pounds.
I think that depends on where you are, as far as the language choice is concerned. But yes, we've stuck with Imperial weights, even though member countries of the former Empire have not. But...
The only difference between the imperial system and the U.S. system is in volume measurements. Not only are the number of ounces in pints, quarts, and gallons all larger in the imperial system, the size of one fluid ounce is also different, as shown in the table in Table 7. 1 (fluid) oz. 1 (fluid) oz.
And far as I know, weights on labels are shown in both pounds and Imperial weights. Not for fresh produced, but for canned and packaged stuff.