For many of us, size zero - that's a UK 4 - is not something we can attain or even want to.
Even so, when the trend hit a few years ago, while many of us were shocked and worried for those of us who might be impressionable enough to try it, we were heartened by the increasing visibility of plus size models on the pages of fashion magazines.
Also, it just seemed to die its own death naturally, once people worked out to get such a body size you'd need to subsist on baby carrots for the rest of your life.
But a more worrying trend has emerged from Hollywood, and that's the clothing size triple-zero.
"American shoppers," wrote Metro, "are now able to buy size triple zero clothes, with very small 23-inch waists, the same size waistband in fact as 6-8 year-old girls would typically wear."
The newspaper was writing off the back of a report from Grazia magazine, which highlighted the trend emerging in the US.
Talking to HuffPost UK Lifestyle, Alex B, a model and writer who also represents older models, says: "Hollywood is constantly infantilising women and this trend is yet another instance of this unacceptable, ultimately coercive treatment of women. Women embracing such extreme thinness are bound to make themselves ill in the shorter and longer term. We should try to stop it."
Dr BJ Epstein, lecturer at the University of East Anglia and HuffPost UK blogger agrees. "What is wrong with our society that women feel they need to look like little children? This is incredibly disempowering, and it means that by focusing on women's looks, we're missing out on what women actually can contribute to the world."
Why would women do this to themselves? While we don't agree with the Mail Online saying it's a 'badge of honour', we do think that in such a highly competitive industry, this has - worryingly - become a new standard to work to.
Rivkie Baum, editor of Slink magazine and plus size campaigner says: "The fact that it exists is pretty frightening. While we can't assume that all women with a 23-inch waist are on a starvation diet,- any more than we can say size 16+ women eat all the time, it is a huge concern that we seem to have come full circle in terms of measuring our self worth by measuring our waists.
"The fact that this trend seems to be trickling down from celebrities and high street brands is hugely concerning as they need to consider their social responsibility to young and impressionable girls. Many professional models have a 24-inch waist (and are on average are still in their teens) - the fact that a triple zero is smaller than their average measurements, suggests that even those we hold as the most slender in our society no longer cut the mustard."
Jes Baker, founder of the Body Love Conference and blogger for The Militant Baker, adds that the size itself isn't the issue, it's the message it sends.
"There isn't anything wrong with having "pencil thin legs" or "sharp collar bones," as many may suggest. Bodies rest at different weights naturally; some of us are small and some are large.
"It's simply a fact of life. Seeing tiny bodies in our media isn't the problem; the permeation of the thought that smaller bodies are worth more is. Not only because it's simply not true, but because it affects all women whether we know it or not."
There may be some good to come out of this. Whereas size zero may have been attainable, because size triple zero is so extreme, it may actually unite women against the quest for super skinny.
"The fact that the triple zero body is so unattainable actually offers a positive opportunity though: to band all women together to reject the impossible body standards we see," says Jes.
"Until now, we have seen a separation of shapes, "straight sizes" vs. "plus sizes." Women occasionally choose to shoot the other down to build themselves up- thin women calling larger women "lazy" and large women calling thin women "sellouts." Neither of these are true, and maybe it takes a standard that no one can truly reach to help us realise that we are ALL IN THIS TOGETHER."
On Twitter, #triplezero is being discussed:
Dr Epstein adds: "Women come in a variety of sizes, and we should celebrate that. Likewise, we should celebrate women's different looks, skills, abilities, and contributions to society. A 23-inch waist is nothing to celebrate; it's shocking and depressing. When will we ever learn that women are more than objects, more than bodies?"