I'm a little on the "fluffy" side as well, and cinching my belt tight enough to keep my pants up while carrying was causing too much pain and discomfort. So I picked up a set of Carhartt 2" wide suspenders and end of problem. I wear an undershirt under an untucked t-shirt or polo anyway, so they work well for me. I carry OWB at 3:00, and with the suspenders I can carry heavier guns like my .327 SP101 with no droop.
https://www.amazon.com/Carhartt-Mens...4-135149aa9081