John Smith:
From what I've read around, the gap varies pretty much from individual to individual to another individual: but the general consensus is that the instant when a person feels he/she's moving past the feeling of simply being overweight, and the instant their obesity starts from truly heaving them down is pretty much a personal odyssey for most people.
They're simply start piling on pounds with moderable to almost none significant sensorial change, then about 100-150 pounds later it nearly all collapses at once: the heightened sensations of physical discomfort and heftiness. The feeling of getting near constantly bloated... the pacing waddle... the spaces that no longer feels nor seems that large neither... their stamina and health plumetting down at an alarmingly fast rate, the bodies who starts sweating over walking a mere couple of steps, how easy they wind out at anything, etcetera etcetera.
I'm kind of hoping that I do somehow hit a sudden point where I notice these changes in this way, because for me the very slight gradual changes are much less satisfying than a sudden realisation or change.