Hiya... I've seen something like this quite a few times, but never as a song. Did a couple of Google searches: one for "diet song"; another for "broken cookies" refining it with a "search within" for "diet" and another "search within" for "calories", ending up with these 78 results.

The "broken cookies" search turns up a lot of "diet rules"/"rules for dieting" etc very similar to what I've seen before; I checked out a half-dozen or so of the links & found no songs, but – if you're willing to check all the links, it's possible you might find one in there.

The "diet song" search turned up a number of songs, but none of the ones I looked at were what you are looking for – though (again), if you have the patience to check out all the links, you might find something.

I do know of a great dieting song (a parody, actually) called "How Can I Keep from Eating?", but it's clearly not the one you're looking for.

Anyway, good luck!