Not just sizes, but ingredients too. I used to drink those Naked Juice smoothies, which were originally just blended fruit with a little bit of apple juice added for liquid. They would write something on the back that said something like “this bottle contains 13 strawberries and 2 bananas”.

Then one day I noticed the drinks were much more runny that usual. I had to search for older pictures people had taken of their bottles, but sure enough all the numbers had changed - and apple juice was no longer a minor ingredient, it was the main one.