This bug is really, really bad and immersion breaking. I strongly agree that it must be fixed.
I love the idea of sliders for low, medium and high calorie food that can be used in game. I actually have made a mod that tweaks the calories and it makes the weight system a lot better for all Zois or so it seems.
This is my thread about it, which shows the values I edited in order to achieve a better, more balanced fitness system.