Having looked into this quite a lot (i have been thin, fat and aspire to be muscular along with having friends on both sides of the divide (bulked up, still obese) i take the view that..
1) Dropping 100lb has a stonking effect in terms of attention from women
2) Going from thin to properly built in the upper body does indeed take it a step further but not as much as the above and anecdotally, they attracted more sluts
3) Biceps, pecks and shoulders are of far more impact and value than abs. To paraphrase a good friend.. 'my abs looked sexy in the mirror but they were useless in clothes'.