We do these (breast reduction surgeries on men) every now and then. Not super often… I’ve been in maybe 10 of them? Of the ones I’ve been in, one was a dude with breast cancer - chopped out the cancer, then chopped down the other moob so they’d heal to be the same size. All of the other ones were gym rats who took steroids and grew some boobs. None were overweight.
I’ve only been in a handful, so grain of salt, but in my experience weight is NOT a factor.
…and this seems like a good time for a plug: Men can 100% get breast cancer. Not often, but possible. If any of you fellas feel a weird lump in your moobs, DO NOT hesitate to get it checked out!!