As king of carnival, the corpulent Rei Momo is supposed to embody all the jollity, carnality and excess associated with that most Brazilian of bacchanals. So when the event's reigning monarch has gastric bypass surgery, sheds 150 pounds and starts an exercise program, you begin to wonder what's going on.
And when six young women die of anorexia in quick succession -- two in the last two weeks -- the wonder turns to bewilderment. Brazil may well be the most body-conscious society in the world, but that body has always been Brazil's confident own -- not a North American or European one.
For women here that has meant having a little more flesh, distributed differently to emphasize the bottom over the top, the contours of a guitar rather than an hourglass, and most certainly not a twig. Anorexia, though long associated with wealthier industrialized countries, was an affliction all but unheard-of here.
But that was before the incursions of the Barbie aesthetic, celebrity models, satellite television and medical makeovers made it clear just how far some imported notions of beauty, desirability and health have encroached on Brazilian ideals once considered inviolate.
By '' 'upgrading' to international standards of beauty,'' said Mary del Priore, a historian and co-author of ''The History of Private Life in Brazil,'' the country is abandoning its traditional belief that ''plumpness is a sign of beauty and thinness is to be dreaded.'' The contradictory result, she added, is that ''today it's the rich in Brazil who are thin and the poor who are fat.''
A generation ago, the ideal type here was Martha Rocha, a Miss Brazil from the mid-1950s. She finished second in the Miss Universe competition supposedly because her body was a bit too generous in the hips, buttocks and thighs, but since those characteristics were so highly valued here, as suggested by cartoons and the popularity of the semi-pornographic drawings of Carlos Zéfiro that circulated, it was the rest of the world whose taste was questioned.
Even the famous ''girl from Ipanema,'' immortalized in the bossa nova song written in 1962, illustrated the cultural differences that prevailed then: only in the English lyrics is she ''tall and tan and young and lovely.'' In the original Portuguese version, the emphasis is on ''the sweet swing'' of her hips and backside as she walks, a sway described as ''more than a poem, the most beautiful thing I have ever seen.''
Today, in sharp contrast, the epitome of beauty is Gisele Bündchen, the top model whose enormous international success has inspired the thousands of Brazilian girls who dream of emulating her to enroll in modeling schools and competitions. But very little about Ms. Bündchen's body -- tall and blond, rangy yet busty -- connects her to her homeland and its traditional self-image.
''Hers is a globalized beauty that has nothing to do with the Brazilian biotype,'' said Joana de Vilhena Novaes, author of ''The Intolerable Weight of Ugliness: On Women and Their Bodies'' and a psychologist here. ''She has very little in the way of hips, thighs or fanny. She's a Barbie,'' one whose parents are of German descent.
Dr. Novaes and others have noted that during the 1960s and 70s, Brazilian girls played with a locally made doll named Susi, who, reflecting the national aesthetic, was darker and fleshier than her counterparts abroad. But in the 1970s, Barbie arrived, and by the mid-1980s, production of Susi dolls had ceased, though it has resumed in recent years in a sort of backlash.
Yet until recently no one here would ever have talked with admiration about having an hourglass figure like Barbie's, let alone the coat-hanger physiques of the international runways. Instead, the ideal was what is known as ''um corpo de violão,'' or ''guitar-shaped body''; that is, like Susi's, thicker in the waist, hips and fanny.
One indication of how rapidly values are changing can be gleaned from a government study released in November, just after the first in the cluster of anorexia deaths, that of Ana Carolina Reston, a 21-year-old model. According to the survey, the percentage of the population taking appetite-suppressants more than doubled between 2001 and 2005, making Brazil the world champion in the consumption of diet pills.
''The reasons are purely aesthetic, not medical, especially for women,'' who account for at least 80 percent of the market, said Dr. Elisaldo de Araújo Carlini, a professor at the Federal University of São Paulo who is the author of the study. ''They want to get thin no matter what, all because of images from north of the Equator. It is a cruel cultural imposition on the Brazilian woman.''
Women in countries around the world are subject to such pressures, of course. But Brazilians argue that the situation here is more extreme: this is, after all, a tropical country in which, much more than the United States, Europe or Japan, people live their lives outdoors, often, for comfort's sake, in skimpy clothes showcasing the body's glories or defects.
A result is a culture of vanity that seems to know no boundaries. This summer, the newest rage, according to local news reports, is liposuction on the toes, and there have also been accounts of a boom in plastic surgery among women 80 and older.
Men are not immune. President Luiz Inácio Lula da Silva is reported to have recently had cosmetic work done on his teeth, and even the chief of an Indian tribe in the Amazon had plastic surgery because, as he guilelessly put it, ''I was finding myself ugly and I wanted to be good-looking again.''
But most of the complaints about the tyranny of the culture of beauty here come from women. Each year follows the same pattern: Enrollment at gyms, here called ''academies,'' declines as cool weather arrives and then rises in the final quarter of the year, as women try to prepare their bodies to look good on the beaches during the Southern Hemisphere summer vacation season, which runs from just before Christmas until carnival, about two months later.
But Brazilian eating habits don't make the process easy. If the emblematic American meal consists of fried chicken, corn on the cob and apple pie, its Brazilian equivalent is more like this: rice and beans, potatoes, pasta, bread, salad and a slice of meat sprinkled with farofa, or ground and toasted yucca flour.
The Brazilian diet is much higher in carbohydrates and lower in protein than is recommended, said Claudia Carahyba, a nutritionist in São Paulo whose clients include modeling agencies that want to break their girls of such bad habits. ''That is especially true of the poor,'' she said. ''Since protein costs more, they trade that for more carbohydrates like yucca, which are cheaper and make you feel full.''
In fact, the new paradigm has been slower to penetrate poorer regions like the Amazon and the northeast, where hunger is still widespread and the idea of ''fartura,'' or cornucopian abundance, is especially valued. There, men in particular are proud to show off wives and children whose bodies are more rounded, as a sign that they are good providers.
''To be fat used to be considered wonderful in Brazil, because it showed that you eat very well, which is important to Brazilians,'' said Roberto da Matta, an anthropologist and newspaper columnist who is a leading social commentator. ''That you have three meals a day and eat meat and beans, calmly, at a table with friends and relatives, means that someone is taking good care of you.''
Experts also agree that Brazilian men, whatever their class or race, have been much slower to accept slenderness as a gauge of feminine beauty. When they are looking for a sexual partner, Brazilian men are consistent and clear in saying that they prefer women who are fleshy in the rear -- ''popozuda'' is the wonderfully euphonious slang term used here -- and have pronounced curves.
In the past, that standard was so firmly established that some Brazilian women resorted to breast reduction or buttock augmentation surgery, sometimes even transferring their own tissue from top to bottom.
But as the international standard has taken hold, tastes are changing.
''Those huge breasts you see in the United States, like in Playboy, were always considered ridiculous in Brazil,'' said Ivo Pitanguy, the country's most renowned plastic surgeon. ''But there is now more of a tendency than before to want breasts that are a bit larger -- not to make them huge, mind you, but more proportional as part of a body that is more svelte and more athletic.''
Though such globalized standards of beauty originated in rich, mostly white neighborhoods, they are gradually being spread to the rest of Brazil and across racial lines by the actresses and models who live here and perform in popular telenovelas. Exercise academies can be found in slum areas, and newspapers noted that the most recent anorexia victim was a dark-skinned teenager from a working-class suburb of Rio who dreamed of becoming a model.
In fact, all six women who died of anorexia lived either in Rio de Janeiro or in São Paulo, the country's most cosmopolitan states and centers of the Brazilian fashion industry. The death that followed Ms. Reston's was of a 21-year-old fashion student. There was also a 23-year-old student and office worker who had a home page on the Web and gave English lessons.
Ms. del Priore, the historian, pointed to other fundamental changes, which she said have led to a rebellion against machismo and the patriarchal structure that she believes persists here.
''This abrupt shift is a feminine decision that reflects changing roles'' as women move out of the home and into the workplace, she said. ''Men are still resisting and clearly prefer the rounder, fleshier type. But women want to be free and powerful, and one way to reject submission is to adopt these international standards that have nothing to do with Brazilian society.''