Also, it seems stupidly easy to make a pregnant woman obese in the game right now. Same with going from malnourished to starving. Fat has some small penalties, for example, but the way they described it, the tier above would have some more severe penalties attached to it. In the dev diary, they said there would be a couple tiers, in essence.
Certain choices in events increase or decrease it, and it is associated with how fat you are.
Well every character has a physique variable. Weight gain and events associated with it.