> Another rule I learned that's pretty much consistently broken these days--at least in the world of advertisement-- is the distinction between healthful and healthy.

I remember a discussion about this ages ago. I had never heard the word healthful until I saw it on this board. So you can probably blame us for the confusion.

Similarly regimen for diet - our diet serves both the slimming and the everday use of the word. I only see regimen used on UK medical sites to do with treatment by a particular drug or cocktail of drugs.