Gyno or fat or ?

[Paa_Paw]

Enlargement of the male breast is called Gynecomastia.  That is true no matter what the percentage is of fat or gland.   In most cases, there is both gland and fat so the distinction makes no sense. 
In your case, I think your problem is largely due to your frequent visits to that famous Japanese town of Obi City. 
OK  so enough of the sarcasm. Seriously, Yes it is Gynecomastia and probably largely due to obesity, but weight loss alone will only make the slightest difference and if you want to get rid of it you will ultimately have to have surgery.  You have made contact with a bunch of older men here, many of whom are, to be polite, well endowed.   They are also older and quite comfortable in their bodies.  Younger men are often more troubled by the condition emotionally and therefore more likely to seek surgery.