Yep, totally true. If you lose the fat you'll hang longer.
A few years back I lost 80 pounds. I was chunky to fat since puberty so I always just thought what i had was good enough. I never worried about much cause even then when changing in the locker room and just fuckin around with friends, I was still holding my own in comparison to them. Flash to me loosing all that fat till I was skinny and Bam! I gained two inches on my length. Yeah, I'm healthy now and happier, but seriously, my dick getting longer is the best fring benefit.