You may have noticed that opera singers tend not to be tiny creatures. Posing behind a staircase bannister only helps a little.
It's an alternate universe in which a 300-pound man can play a teen-age boy and a 250-pound woman can be a "nymph".
None-the-less, imagine trying to cast the lead in "Satyagraha", an opera by Philip Glass (Philip Glass Philip Glass Philip Glass Philip Glass Philip Glass... that guy) about the famously thin Mohandas Gandhi. You can read about the new Metropolitan Opera production in a New York Times article Opera About a Giant’s Life, Complete With Giant Puppets in which they duly note that singer Richard Croft lost "10 pounds" for the role.
This seems to have gotten him down to somewhere between Jesse Ventura and Mussolini, I'd say. If only Ghandi had been known for wearing more slimming colors.
The NY Times also has a nice video piece about the staging and large scale puppetry in the production.