Good name pun, though
Remember Moe-tan? Now there's Moeru Diet.
Presumably the idea is to lose so much weight that you actually become two-dimensional, and can date the girls depicted therein. (One of whom, the heroine, is a maid and calls you "master" (go-shujin-sama), natch.)
Wimbrel:
I don't care what regimen of diet and exercise is necessary if it will give me that rippling chest.