What is the hottest cause for someone who's been maintaining weight, to suddenly start gaining?

When they love being fat as much as I like fat.

Exactly the same. My wife has big legs, and they always start to float, so she puts them under mine.

I understand your fascination for the number on the scale. It does not define them or you in anyway, but you are still somehow dying to know it. I think 4 months is probably a bit soon. It takes a lot of time, trust, being comfortable with someone and often also confidence in one self to share such intimate personal details.
My first wife never told me, but she was also not comfortable with me touching here belly. My second long term girl friend was quite open about it, but she had undergone WLS recently and told me how much she weighted, how much she lost etc.
My current wife told me a few years into the relationship when she was trying to loose some weight. I don't think I had asked her before. We also did some measurements at that time. And now she tells me regularly.

Communication is important in a relationship, but I don't think you need to tell everything immediately. There is a time and place for everything. Just like her wieght might be very private for her, your kinks might be private for you. It all depends on where you are in the relatiosnhip, and how important it is for you. I was pretty clear from early on that I prefer bigger women. Later on I added that I like big bellies more than boobies.
I would love to see her at 400 lbs, but it is also pretty clear that she is not comfortable being more than about the 300 lbs she is now, and that is absolutely fine with me, so I have never brought that up.

I never had an "awakaning" like this, this kink has always been with me for as long as I can remember.
But reading all these stories makes me wonder: did these episodes that are mentioned here start your fat fetish, or was it rather awakening something that was there already for a long time but somehow you missed the signs and now you could connect the dots?

I will need to travel to the US more often in sumer :-) Now if only they would start doing that in Belgium also...

I have the same experience. I once over ate on purpose to the point that it hurt and I was so suprised that was I was so hungry the next day. I expected the opposite. I did not indulge the next day because I had to work, but I think if you did, you could increase your appetite very quickly and gin a lot of wieght.

I have been fascinated by big bellies for as long as I remember.

Question for the people who got some kind of "awakening" after seeing a cartoon or so: do you think that cartoon is the origin, or did it just trigger something that may have been present already, but maybe you didn't realize?

When I was in Las Vegas a few weeks ago, I was pleasantly surprised that there were quite some women revealing part of their belly. It was usally the upper part of their belly (between their high rise pant and their top), so no rolls or belly hang visible. But still nice to see that plus size women are now also showing more skin.