My grandfather complains that I drink too much Mt. Dew (even though I drink less than half of the recommended maximum). So I say, you know, you're right, I should cut down on the sugar and drink Diet Mt. Dew. [Also, the times I've bought Diet MD it actually lasts twice as long because I tend to drink half the can and leave the other half for tomorrow. It's strange but I've noticed I do that.]
I write Diet Mt. Dew on the shopping list.
He brings back a case of regular because "oh, it's cheaper if you buy the case, and there wasn't a case of diet".