5'0, 100lb Opera singer here.  The Role of Brunhilde is typically sung by a tall, hamplanet type because they can use their excess lard as a means of compressing their diaphragm to get out the sound necessary to carry over a 100-120 piece orchestra. I have seen many performances of the Ring cycle and I think the thinnest Brunhildes I have seen are at the upper part of a healthy BMI going into the smallfat territory. Anne Evans is probably the closest I have seen to a Human-sized Brunhilde.   Title Here   Wagnerian Opera is also pretty easy to sing at the baseline.(With a couple of exceptions) The singer just needs to be able to generate a ton of volume.  The Hamplanet sopranos typically will weasel out of learning proper breathing, technique, posture, etc and just have their mass do the work for them. Proper Opera is sung without amplification so even if it's an easier piece, you still have to know how to carry over an orchestra without injuring your vocal cords. You can hear how much better Evans sounds than Deborah Voigt. Dame Gwyneth Jones may have been in an upper healthy BMI range when she sang Brunhilde, too.  When you compare them to the women singing it now...Blech. Those Obeasts aren't singing, they're fucking shouting. Some of Jone's Brunhilde:  Title Here Since the Costume is kinda obscuring her shape in the above: Title Here What the Hams can't do consistently in the world of Opera is intricate, ornate music. Mozart, Vivaldi, Bellini....The earlier Verdi stuff. Because it requires your core muscles to be in good shape. You have to do it for three to five hours at a time, in twenty pounds of costume, on a 90 degree stage. Most contracted singers are required to stay within a healthy weight range. Several planets have been injured by becoming entangled in their own Girth. Lots of the companies in the EU have to pay much higher insurance for the Fatties to play Opera. So it's happening less and less.