“…while these largely provide men with underwear of a sporty fashion, a little extra elastic can do a lot more than add some masculine style. Longer measurements in the elastic department appeal to brand-conscious men keen on representing their fashion sense. Underwear designed with wide waistbands can also use the extra elastic for a more contoured fit that’s slimming around the waist”
More at: http://www.underwearexpert.com/2015/05/wide-waistbands-part-two-quick-thick-style/
Image from underwearexpert.com