Neither part of that is true. If you sell French fries which cost you $1, and you sell them for $2, your profit is $1. If you can raise the price to $3 then you

Neither part of that is true. If you sell French fries which cost you $1, and you sell them for $2, your profit is $1. If you can raise the price to $3 then you’ve doubled your profits. But your customers know that French fries are bad for their health, and so year after year they promise themselves that someday they will quit French fries completely. When you raise the price to $3, that is when they decide they can really quit.