*is there a way to make the player actually look fatter in the game if he eats to many calories?
A magic bag would be cool, the Fallout versions handled it by letting your turn robotic companions into walking (or floating) refrigerators.
I'd love it if there was a fat slider, but just having a muscle slider is pretty cool. I'll have to wait for the right SKSE functions though before I have any control over it.

I'm about to put together a patch for Frostfall that will have your body warmth effect your morale. If that turns out to be popular, we might be able to do something more elaborate in the future. At the moment, the only change he has to make is to publish his warmth number to an unused global that I can check, but fat insulation would take a bit more work.
Edit: to clarify, I was not using 0.23 when this occurred. I haven't installed the update you just posted yet.
I haven't looked over that mod yet but I've already had similar reports. I'd try loading IMCN - Overrides.esp later than that mod and seeing if it fixes it. If not some sort of patch may be needed (I'm guessing its just that he edits food costs, which overrides my food changes if his mod loads later than mine.)