Somewhere in the world is a yoga teacher who gained 40 pounds on purpose for a personal experiment. And she called it an art project.

Trina Hall's diet was something like "see it... eat it," and when she gained weight, she felt awful about herself, fearing that she'll "die alone, probably from choking on a potato chip." But then she learns some life lessons and becomes thin again. YogaDork explains why Hall's experience is a problem:
Gaining weight to feel what ‘fat’ feels by eating tons of “bad” food, then stopping it all by going back to eating “healthy” is not a luxury we can all afford. Hall is, of course, free to do what she wants with her own body and feel whatever she feels, but I wonder if her public story of personal disempowerment due to weight and body image issues is a great triumph in unmasking what many others feel inside their skin, or demoralizing and insulting to those with larger bodies who are trying to lose weight or who otherwise feel completely comfortable and confident exactly where they are.
It's important to remember that Hall had the privilege of being thin and pretty, and that her weight gain was purely experimental. The fact that she could revert back to her old self is not something many yoga practitioners and other women are able to do in a snap.