Gaining

Well why don't you tell them that you are going to lose enough weight to be more healthy than you are but not to the point that you look svelte or thin. You'll still have some thickness ie your belly to you. Then you can go about stuffing. Plus, since you'll have to be on a different healthier and probably stricter diet that first stuffing will feel oh so wonderful. There's your goal right there. I'd wager a few buttons will get popped in the process.

It would also be somewhat interesting if you were in to humiliation and happened upon a feeder who was also a physical trainer or nutritionist. LOL