In Madrid Spain's top fashion show kicked off after causing a storm with a ban on skinny models and one well-known designer said he had to replace all the girls in his line-up.
A similar controversy in brewing is London where pressure has been growing on the organisers to also ban ultra-skinny models following the Madrid clamp down.
The edict has caused uproar among designers and put dozens of models out of a job unless they bulk up fast.
Plans in chaos
Antonio Pernas, whose 1960s-inspired collection marked the start of Madrid Fashion Week, said the rules banning overly-thin models had thrown his and others' plans into chaos.
"I had to change the whole lot in one day -- 18 models. It gave us problems, but look, this industry sets an example to young women. We want to project a healthy image, so I'm not against the measures," Pernas said.
Organisers, under pressure from Madrid's regional government, which sponsors the show, imposed restrictions on any model with too low a body mass index (BMI) - a measure based on weight and height.
BMI measures body fat based on height and weight; it is thought that a model measuring 1.75 meters in height would have to weigh at least 55 kilograms to comply with the stipulation.
The show's director, Leonor Perez-Pita, said some models last year "really were too thin" and welcomed the restriction that they must have a BMI of higher than 18.
"I think it's fantastic. They look beautiful. I don't want skeletons on the catwalk. Clothes look much better on a lovely girl than on a clothes hanger," she said.
The Madrid ban set off a storm in the fashion world, which has seen a trend for super-slim "size zero" models.
Britain's culture minister and the mayor of Milan, regarded as the world's fashion capital, have already called for similar rules.
The British Fashion Council had to scrap a photocall in London after a barrage of criticism for not following Madrid's lead.
Agencies make huge changes
Blanca Zurita, assistant to Spanish designer Fernando Lemoniez, said the weight debate threatened to overshadow months of design work.
She said the show's casting agency had been forced to make huge changes after a large number of models failed to make the weight.
But Ester Garcia, who runs the agency, said only one girl had not made the grade while another five chose not to attend.
Backstage, models seemed unfazed by the controversy. "As long as it doesn't affect me I'm not too worried," said Caroline Duong who was rushing to get ready for Lemoniez's show.
But in London big names and officials will have a hard time avoiding such questions for the duration of the five-day, 50-show event, being held at the city’s Natural History Museum.
As London kicked off celebrities gave supportive applause to Lily Cole, the elfin, redheaded teenager frequently mentioned in the skinny models row.
The restrictions have triggered media speculation about whether models like Cole and Kate Moss, reportedly 1.68 metres and 49 kilos, could be affected.
Hilary Riva, chief executive of the British Fashion Council, which organises the event, has said that the organisation "does not comment on or interfere in the aesthetic of a designer's show" while council chair Stuart Rose has indicated he is not in favour of legislation.