Cecilia Bartoli, one of the world's most famous Opera singers is most definitely not a fattie; in fact she's fairly hot.

http://www.deccaclassics.com/artists/bartoli/index.html

Another theory might be that Opera singers are just particularly apt to a hedonistic lifestyle which involves double portions on the after-the-curtail buffet, tripple champagne and that young bariton over there for a desert, please.

I also wondered if successful opera singers enjoy the good life including rich foods.