Bought an oversized (even for me) button shirt last year, maybe a 7XL. Put it on yesterday, suddenly it seems like it's moving less oversized and more a correct fit.

Not "public" public, but I broke a toilet seat at work last week. I guess it just took too much weight. Made a big crack through one side.

Keep eating, flabby...
One day you'll grow fatter than me.

Boxer briefs are definitely a go to for me. The legs do stretch, but not as much as boxers. There's also a kind of seam that keeps legs separate from junk.
I'm hefty enough (3 or 4XL, with stomach laid over,) that not only do my legs constantly rub, but I also have a sizeable fupa, and those seams really help with rubbing.
Only problem is they start to wear holes between the legs, and a pack of Hanes I got a while back wasn't sewn up around the waistband properly.

At what point does a BBW or BHM (or BNB, I think) become fat enough to be considered super-sized to you? Is it when they're too big for folding chairs? When their belly smothers their privates? When they brush both sides of a doorway?

More behavior-wise, but anyone who already overeats. Metabolism slows with age, and hunger usually won't.

In addition to bigger bodies needing more calories, it's likely you've stretched your stomach AND conditioned your brain to want more. I've done the same thing.

6'2", ~433 pounds
56 inch jeans, 5 XL shirts

Measure each contestants waists, give them shorts 2 or 4 inches too small. Stuff them until the buttons pop.
For an easy contest, sewn on buttons.
For hard, riveted jean buttons.

I also grow muscle fairly easy, but I guess I just grow fat easier. Maybe potatoes might do something for you?