[KyleGoetz]

Having only lived in Japan a year and no longer speaking Japanese on a daily basis, I have little means to pick up on the subtleties of the language anymore (sadly). Thus, I register (to hopefully stay) and come to you, Japan Forum, to help me.

I've seen both 食べたくはない and 食べたくない. What is the difference between them? My best guess is that 食べたくはない is the "correct" formal version, and 食べたくない is a variant that is used most often nowadays in less-than-formal situations. Perhaps how most people use だから but in formal speeches you would use したがって?

Are there other times when this sort of は-insertion occurs in between forms? I realize that, technically speaking, 食べたくない is not one word, but two, the conjunctive root 食べたく and the negative of ある, ない. This is what makes the は-insertion linguistically cromulent, right?

Thanks!

Edit: The only thing I can figure is that, since one use of は is to use in two phrases next to each other for contrast, e.g.:
私はアメリカ人だけど、キムさんは韓国人だ。
Thus, I'm guessing maybe you need the は if you are contrasting what you don't want to do with the fact that you have to or something.

So, maybe 食べたくはない has an implied continuation of けど、食べなければならない?