For many men, stress puts on weight.
Further, many women, once they have locked down a guy want him not to stand out as much so as not to be stolen. So, she sabotages his eating and work out schedules.

And having a six pack takes crazy amounts of work out and diet. (and often water dehydration just before photo shoots)

I do not have any good / solid pattern that describes wimynz pulling of the fat-grenade.
One could just say that wimynz are lazy, but that is not the whole of the story.

(my best working theories revolve around a half-dozen mental-emotional eating disorders. eg The weight could be taken off only through psychology sessions. And wimynz usually have 2 or more of these, and thus... blimp)

Wimynz also rate most men "below average" in looks. Like 80% of men are rated below a 5 (1-10 scale). And from this, we see most wimynz talk as, and acting as, they are in competition for (that they have a chance) that top 20% of men.