I work making grocery store circulars, so I always notice it. EVERYTHING has gone down in size.
The big jug of OJ used to be 96 oz, is now 89 oz. Tuna used to be a 6 oz can, now 5 oz. Peanut Butter used to be an 18 oz Jar, now a 16 oz. Capri Suns and the like (juice pouches) used to be 6.75 oz/ea, now only 6. You used to commonly see Coke/Pepsi 2L Bottles for 10/$10, now its 1.5L bottles. Spaghetti sauce used to be a big 32 oz. Jar, now its only 26 oz. Cereal boxes vary but all are smaller. Haägen-Dazs Ice Cream is no longer a pint, its 14 oz. Mayo used to be a 32 oz. jar, now its 30 oz. Ice cream used to be half a gallon, 64 oz. then it went to 56, and now it's 48 oz. Items in a can, like veggies or spaghettios, used to be 16 oz and all are now 14.5-15 oz. What used to be a 1lb bag of pre-mixed salad is now 12 oz. I won't even mention the size of potato chip bags...