If any reminder were needed that ballet's delicate image comes at the cost of discipline as brutal as can be imagined, two stories in recent weeks serve the purpose.
First, a reviewer on The New York Times, Alastair Macaulay, controversially criticised the prima ballerina Jenifer Ringer for her weight. Commenting on Ringer's performance as the Sugar Plum Fairy in the Christmas classic, The Nutcracker, Macaulay wrote that she "looked as if she'd eaten one sugarplum too many".
He also wrote that Jared Angle, in the role of the Cavalier, looked as though he had: "been sampling half the Sweet realm", but it was his comment about Ringer that caused outrage, especially once it emerged that she had struggled with eating disorders in the past. The story made headlines around the world, juxtaposing Macaulay's comments with photographs of Ringer as the Sugar Plum Fairy, in which she looks about as far removed from fat as possible.
The 37-year-old dancer took to the talk-show circuit to give her perspective on the furore. Speaking on NBC's Today Show, she said firmly that she was not overweight, and simply had "a more womanly body type than the stereotypical ballerina".
But while she said Macaulay's comments were "embarrassing" and had made her "feel bad", she refused to join those calling on him to apologise for having remarked on her size at all. "As a dancer, I do put myself out there to be criticised, and my body is part of my art form," she said.
Macaulay isn't the first person to run into trouble for criticising dancers' physiques. In 1999, Derek Deane, the chief executive of the English National Ballet at the time, told the Sunday Times that he had had to recruit dancers from abroad because British ballerinas were "too stocky" and "too pear-shaped", something he blamed on their "poor eating habits". The only exception in Deane's view was the principal dancer at the Royal Ballet, Darcey Bussell.
It's not hard to see why that kind of talk upsets people. Ballet dancers begin their training young and come under tremendous pressure to maintain trim physiques.
While estimates of the numbers affected vary, eating disorders such as anorexia and bulimia are problems for many dancers. In 2000, a 15-year study of ballet schools in the UK found that student dancers were routinely expected to be 25 per cent under the average body weight.
Even without the pressure to control their weight, the physical demands on dancers are extreme. To the audience, the dancers may look as though they are moving effortlessly through the air and on their toes, but it is a job that requires steely self-discipline and an iron will - both of which are needed to help a professional dancer cope with the all-consuming training schedule.
Even pretending to be a ballerina can be gruelling. The actress Natalie Portman, whose new film, Black Swan, has just been released in several countries, has been talking about her regime to get into shape, which started a year before filming even began.
She started with two hours' training a day, which increased to five hours a day six months into her programme. And finally, as if that weren't enough, for the two months before filming started, she trained for an eye-watering eight hours a day.
Unsurprisingly, the already slim actress is said to have dropped 20lb as a result. In an interview in the latest issue of US Vogue, the actress said of her backstage work for the movie: "The discipline was good for the part - it hurt a lot; your body is in constant pain." Her co-star Mila Kunis also lost 20lb, and has said that by the end of her training for the film she "looked like Gollum".
Macauley has since defended his right to comment on dancers' bodies. In a later piece in The New York Times, he said ballet was particularly unforgiving of what he described as "surplus weight".
"If Ms Ringer performed flamenco or Bharatanatyam or most forms of contemporary dance, she would look extremely slim," he wrote.
"I am severe," he concluded, "but ballet, as dancers know, is more so."